> For the complete documentation index, see [llms.txt](https://support.caspen.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://support.caspen.com/using-caspen/billing/payments/apply-an-existing-payment-to-an-invoice.md). # Apply an existing payment to an invoice ## **Overview** If a client has made a payment that has not yet been used, you can apply it to an invoice once the invoice is **finalized**. *** ## **Apply an existing payment** To apply an existing unallocated payment: 1. Go to **Billing** → **Invoices** and open the invoice (Actions → View, or click the invoice number). 2. Click **Pay invoice** → **Existing payment.**

A list of the client's **unallocated payments** will appear. 3. Enter the amount you want to apply. 4. Click **Apply**.

The applied amount will appear under the **Payments** section of the invoice.

The invoice’s Payments section shows the applied payment and the allocation number.

The **Payments** section shows the payment and the allocation number. *** ## How allocations work When a payment is applied to an invoice: * The invoice displays the payment with an allocation number * Clicking the allocation number opens the **Allocation** screen * From the Allocation screen, click **Allocated from payment** number to open the original payment record The Allocation screen shows:

The Allocation screen displays the allocated amount, allocated from payment, and allocated to invoice.

* **Allocated amount** (how much was applied) * **Allocated from payment** (the payment the money came from) * **Allocated to invoice** (the invoice the money was applied to) In the payment record:

*The payment record shows the amount marked as **Allocated** and lists the invoices it was applied to.*

* The payment shows an **Allocated** amount * The **invoices** that received the payment are listed * The payment and invoice link to each other for easy tracking This is especially useful when: * One payment is split across multiple invoices * Reviewing which invoices were paid using a prepayment or bulk payment *** ## **How to unlink an allocation** Payment allocations can only be removed from the **Allocation** screen. To unlink an allocation: 1. Click the **allocation number** on the invoice. 2. On the Allocation screen, click **Delete**. The allocation will be removed, and the amount will return to **Unallocated** in the payment record. --- # Agent Instructions This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com. ## Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter, and the optional `goal` query parameter: ``` GET https://support.caspen.com/using-caspen/billing/payments/apply-an-existing-payment-to-an-invoice.md?ask=&goal= ``` `ask` is the immediate question: it should be specific, self-contained, and written in natural language. `goal` is optional and describes the broader end goal you are ultimately trying to accomplish on behalf of the user. GitBook uses it to tailor the answer towards what is most useful for that goal. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.