I'm trying to launch our Odoo (v16 odoo.sh) eCommerce website, which we're looking forward to having, as it's part of the reason we switched to Odoo, but I can't find the answer to what I think is a really easy configuration setup.

Our customer base includes many repeat (B2B) customers - that is, they are ordering from us regularly, and before eCommerce, we happily provided them credit terms.  So, they'll place their order and provide a PO number, and we'll confirm their order, ship the products and send them an invoice to pay in 30 days.

I'd like to allow them to place their orders on the site, but I can't find a way to have them specify their PO number.  It seems that we're missing a Payment 'provider' that simply gathers a PO number and says 'thanks'.

Note- this payment option isn't available to just anyone - they need to have gone through a credit approval process, but surely it's possible.

I found this old post, which refers to a "Custom Payment Acquirer", but I can't find that in the Apps or payment methods.  https://www.odoo.com/forum/help-1/how-to-add-customer-payment-terms-in-ecommerce-134721

What am I missing?