HI @Yvonne13
is that for new account activation?
if you have activate recently, stopped at payment and waiting for the sim to come to complete it, then, please download PM app and complete the activation and enter the new sim card number
But if you are customers here and just replaced sim card and phone due to lost, then login to My Account, use email to receive 2FA code and go to Profile page to update new sim card
or you can submit ticket with agent if you cannot login My Account:
https://productioncommunity.publicmobile.ca/t5/notes/composepage/note-to-user-id/22437
