new account or you are PM customer already?
for new account, just download the PM app and start subscription
but if you are already PM customer and got a new sim, then login My Account > Profile and use the pencil beside sim card number and update (if you cannot receive 2FA on phone to login, just click Didn't receive code and choose email to get the code)
if you cannot login, then ask PM to help., just message them
https://productioncommunity.publicmobile.ca/t5/notes/composepage/note-to-user-id/22437
