From your SnapCall interface, go to the bottom and click on the Sharing button, then click on "Share a link".

A new window will appear. Now, you will be able to share any payment request with the call participants.

Copy & paste your link and click on "Request payment".

Your payment request has just been sent to your contact.

You can also generate your invoices on the fly and send them automatically to call participants. It's up to them to pay you whenever they want.