Allocating payment to an invoice

I uploaded a qif file from bank
I have 20+invoices each to different people
I looked at the transactions and edited them appropriately to have the name of the person
The invoice is still outstanding!
How do you allocate the payment to the invoice!

please provides steps or a comprehensive guide on how to do this.

Have a look at

Under heading " Receipts against sales invoices" it shows how to allocate transaction to specific sales invoice but typically you’d not select the invoice and let Manager to allocate to invoice automatically (easier).