SOS signal and no sim on iPhone 13. No phone service

Remove and reinsert the SIM card.

Contact your carrier.

See also these Apple articles below:

If you see No Service, Searching, or SOS on your iPhone or iPad

If you see No Service, Searching, or SOS on your iPhone or iPad - Apple Support

Manually update your carrier settings on your iPhone or iPad

Manually update your carrier settings on your iPhone or iPad - Apple Support

Update your network provider settings manually on your iPhone or iPad

Update your network provider settings manually on your iPhone or iPad – Apple Support (UK)

If you see a Cellular, Ultra Wideband, or Apple Pay Issue message after an iOS update or restart

If you see a Cellular, Ultra Wideband, or Apple Pay Issue message after an iOS update or restart - Apple Support

My I phone 13 not working it’s saying sos

I did that it’s still not working

Contact your carrier.