What is the “Request Payment” feature?
Select the Due Date (Pay-by-date) and choose the users (or provide external contacts)
to whom you want to send the payment link, with a proforma invoice for completing
the payment.

Once you click “Request”, the payment link is emailed to the selected users.
This requested order gets automatically added to the “pending orders” section with a “Pending” tag
Where can I check all pending orders?
How to check details for a pending order?
On this page, you can view the invoice by clicking on the Proforma Invoice number
To make the payment by click on the payment “Link”. It will open the payment page:-