On EM7565, in case you need to setup a username, password and authentication to access a specific APN, you can easily setup those parameters using Linux SDK API or even Windows 10 GUI (Network & Internet > Cellular > Advanced Option > Add an APN).
In case your only option is AT command, you can rely on non-documented command AT$QCPDPP. Syntax description can be found in the following document.
1- Only refer to this document for the syntax of the QCPDPP command. For any other command, you need to refer to official guide:
2- This command not being documented implies that it was not fully validated. You need to test thoroughly to ensure it meets your requirement before any deployment