You can record payment for non-inventory and inventory purchases directly on a purchase invoice as you are creating creating it and make an immediate payment before saving. A single payment type can used.

There are also several other ways to pay suppliers (including regular payments and applying credits).

To accept an immediate payment for a purchase invoice
* indicates a required field (other fields are optional)

Navigate to Accounts Payable > Purchase Invoices. Or click the Purchase Invoices toolbar button.
The Purchase Invoices window opens and all PIs created today are listed.

Add a purchase invoice as you normally would.
Ensure the mandatory information (and optional information, if needed) is completed.
Add, edit, import, or link to products and services as needed.

Click the Taxes & Credits tab.

(optional) Check any Available Credits you want to Apply to this purchase.

Select the Make a payment now check box.

In the Payment Type* dropdown, select the method of payment from the list.
A default payment type may be automatically selected if it has been set up in your supplier settings but can be changed.

In the Payment Amount column, optionally change the amount to a maximum of of the PI value (less any credits applied).
The remaining purchase invoice total is entered by default.

Enter a Tracking/Cheque # to record a manual cheque number or EFT tracking/reference number.
(if you are printing a cheque from agrē or adding to an EFT batch that field will be populated automatically at the time the cheque is printed or the EFT batch is confirmed)

Type any Payment Comments.

Click Save.
The payment is applied and the supplier's account is updated accordingly. You can no longer edit the purchase invoice without unapplying the credits from the immediate payment.
(Config U, L,C) A message appears asking you if you want to preview.

Click OK. 
Click Cancel if you do not want to preview the report.