I lost my SIM card how do I get a verification code for my iPhone

See if anything here helps.  If necessary, you can use account recovery as explained in the link at bottom of the article.

Verification code - how to get one and sign in with two-factor authentication.   *

If you can get a code to sign in, do what is posted above to change your number.

👉 Sign in to your Apple ID account page and edit / update your Apple ID details.

https://appleid.apple.com

-> edit your trusted phone number.