Registering

[Bob_pat01]

I have canada usa Mexico plan. Now in USA. I can text but not phone. Error says I am not registered   I try to register it looks good but is there a setting I need to change

[BKNS27]

@Bob_pat01 

First check to see if your phone is VoLTE compatible. Not all phones works in USA.

https://www.publicmobile.ca/en/get-help/articles/volte 

If it is then manually connect to AT&T, T-Mobile or Verizon network.

[softech]

@Bob_pat01 

What phone do you have? Mobile data works?

Critical part to US roaming depends on T-Mobile/AT&T/Verizon coverage and whether you can connect successfully onto either network.

If the phone is not connecting to T-Mobile/AT&T/Verizon, change the Network Connection from Automatic to Manual and select and test each of the three and see which one you can connect and work best

If your issue is with data, make sure your Roaming Mobile data is enabled and you have disabled your mobile data limiter.  Also change your network mode to 4G (and don't try 5G until you can connect and works on 4G)

If your issue is with voice, use the IMEI checker to check if your phone is VoLTE whitelisted by PM here:
https://www.publicmobile.ca/en/get-help/articles/volte

If your phone is capable with PM's VoLTE, you might want to enable VoLTE on your device if you see the option there (although most phones would have that enabled already and the option is hidden)
If your phone is not on PM's VoLTE whitelist, you might need to use some VoIP app like TextNow as a workaround