An invoice arriving in a shared finance mailbox should not trigger a chain of forwarded emails, handwritten notes and a last-minute question about who approved payment. This Power Automate invoice approval example shows how an SME can turn that familiar friction into a controlled process using Microsoft 365 tools it may already own.
The aim is not to build a complicated finance system in Power Automate. It is to give the right person the right invoice, record their decision, chase it when necessary and leave finance with a clear audit trail. For many organisations, that is enough to remove a surprising amount of manual work.
What this invoice approval process solves
A workable approval flow addresses three operational problems at once. First, invoices stop sitting unseen in a mailbox or folder. Second, approvers no longer need finance to repeatedly ask whether a purchase was authorised. Third, the payment team can see the invoice status without searching emails or maintaining a separate spreadsheet.
This is particularly useful where purchase orders are not consistently used, department heads approve their own spend, or finance is handled by a small team. It does not replace an accounts payable platform where you need advanced matching, supplier management, payment runs or statutory controls. It does, however, provide a sensible step between an unmanaged inbox and a larger finance transformation.
Power Automate invoice approval example: the business scenario
Consider a 75-person professional services firm. Supplier invoices arrive as PDFs in accounts@company.co.uk. Finance needs each invoice checked by the budget holder before it is entered into the accounting system. Invoices over £5,000 also require a finance director’s approval.
The business uses a SharePoint site as the central register. Each invoice is stored in a document library, with columns for supplier, invoice number, invoice date, net value, VAT, total value, cost centre, approver, status, due date and accounting reference. The original PDF stays with the record, rather than being copied between inboxes.
The flow begins when an invoice is added to the library. Finance can upload it manually, or a separate flow can save email attachments from the shared mailbox into the correct location. The important point is that there is one agreed route into the process. A workflow cannot compensate for invoices being left across personal inboxes, Teams chats and desktop folders.
Step 1: Capture the invoice details
When the file arrives, the flow creates or updates the SharePoint invoice record and assigns an initial status of “Awaiting review”. Depending on the volume and consistency of invoices, finance may enter the key values in a simple SharePoint form, or use Power Apps to make the data entry screen clearer.
For invoices with predictable layouts, AI Builder can extract fields such as supplier name, invoice number and total. That can reduce rekeying, but it should be treated as assisted data capture, not unquestioned automation. Supplier formats vary, scans can be poor and a misplaced decimal point is not a small error. Finance should be able to review extracted values before the approval begins.
At this point, the flow determines the budget holder. The simplest method is a SharePoint reference list mapping each cost centre to an approver. A more mature version can use a purchasing register, project list or line-manager data. Keep this logic visible and maintainable. If only one person understands why an invoice goes to a particular approver, the process will become difficult to support.
Step 2: Send an approval with enough context
Power Automate sends an approval request to the budget holder through Teams, email or both. The request should include the supplier, invoice number, amount, due date, cost centre and a direct reference to the stored document. It should also ask a useful question: is the service or goods received, and is the charge expected?
Approvers need a clear choice. “Approve”, “Reject” and “Request clarification” are usually more useful than a generic yes or no. A comments field is essential, especially for a rejection or a query. It saves finance from reconstructing the reason later.
For invoices below £5,000, an approval can move the item straight to “Approved for processing”. For invoices at or above that threshold, the first approval triggers a second request to the finance director. This is sequential approval. It is appropriate where the second approver needs to know that the budget holder has checked the invoice first.
Parallel approval is another option, but use it carefully. It can shorten the cycle where two people can independently approve an invoice, yet it can also create confusion if one approver rejects it while another approves. The correct design follows the organisation’s delegated-authority rules, not what happens to be easiest to configure.
Step 3: Update the record and notify finance
Once the required decision is made, the flow updates the SharePoint record with the status, approver name, decision date and comments. Finance receives a notification only when there is an action to take: process the invoice, investigate a query or contact the supplier.
This distinction matters. A busy finance team does not need another stream of workflow messages confirming routine activity. The SharePoint register is the working view. It can be filtered to show invoices awaiting approval, approved but not posted, rejected invoices and items approaching their due date.
After the invoice is posted in the accounting system, finance enters the accounting reference and changes the status to “Processed”. If there is a suitable integration with the finance platform, this update can be automated. Where there is not, a controlled manual update is often the better choice than a fragile workaround.
Build reminders and exceptions into the flow
The approval itself is only half the design. The real value comes from what happens when normal behaviour breaks down.
A sensible flow sends a reminder after two working days, then escalates to a named deputy or finance manager after a further agreed period. Do not let every overdue invoice automatically go to a director. Escalations should reflect the business’s authority structure and the invoice due date.
The flow should also handle an approver being away, an invoice arriving without a cost centre, duplicate invoice numbers and approvals that time out. These are not edge cases in a live finance process. They are routine conditions that need agreed ownership.
Use clear statuses rather than attempting to infer meaning from a comment or an email subject line. A practical set might include Received, Awaiting review, Clarification required, Awaiting second approval, Approved for processing, Rejected and Processed. Keep the number manageable so staff use them consistently.
Controls that make the workflow defensible
An invoice approval flow can create a useful audit record, but only if the underlying design is disciplined. Approval history should record who decided, what they decided, when they decided and any comments provided. The document should remain available with that history, subject to the organisation’s retention policy.
There are four controls worth agreeing before the flow is built:
- Approval limits and delegates, including what happens when the usual approver is absent.
- Access permissions, so staff can only view invoices appropriate to their role.
- Duplicate checks, usually against supplier and invoice number, with a route for legitimate credit notes or repeats.
- A change process for thresholds, cost centres and approver mappings, so rules do not quietly drift.
Avoid giving every finance user permission to edit every approval field after the fact. SharePoint permissions, version history and separate views can provide sensible protection without making the process hard to run. For higher-risk environments, the workflow should be reviewed alongside finance policy, segregation-of-duties requirements and the capabilities of the accounting system.
Common mistakes in Power Automate invoice approvals
The most common mistake is starting with the flow rather than the process. If nobody has agreed who approves a marketing invoice, or whether a project manager can approve spend after the work is complete, Power Automate will simply make an unclear process faster.
Another is relying entirely on email. Email is useful for notifications, but it is a poor system of record. SharePoint provides the register, document storage, permissions and searchable history that email lacks.
It is also easy to overbuild. OCR, complex supplier matching, multi-stage conditions and accounting integrations all have a place, but not necessarily in the first release. A small, reliable flow handling the majority of invoices is more valuable than a large design that finance cannot maintain. Start with the approval rules that matter, then improve the process using real exceptions and feedback.
Finally, check licensing early. Standard Microsoft 365 capabilities may cover SharePoint, Outlook, Teams and basic approvals, while AI Builder, premium connectors or connections to certain finance systems can introduce additional licensing requirements. This is a commercial consideration as much as a technical one.
A sensible route to implementation
For an SME, the right first step is usually a short process review: map invoice types, approval thresholds, existing data sources, exceptions and ownership. From there, build a focused pilot with a small group of suppliers or one department. Test reminders, rejections, delegated approvals and duplicate handling before rolling it out.
ThePoint often sees the best results when the workflow is treated as part of a wider SharePoint operating model, not a standalone automation. Clear document storage, a usable register and straightforward support arrangements make the process easier to adopt and improve over time.
A good invoice workflow should make the next action obvious, not add another system for people to remember. If finance can see what is waiting, managers can approve from where they already work and every decision is recorded, the process is doing its job.