I can’t make a new Apple ID cause it’s saying my phone needs updated but the number is wrong

but the number is wrong

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

https://support.apple.com/en-us/HT201354

Change & check your data (Security, Account, Payment & Shipping) associated with your Apple ID.

Check & edit trusted phone number:

I can’t make a new Apple ID

See this Apple article: Sign in with your Apple ID

https://support.apple.com/en-us/HT204053

👉 Use one Apple ID to access all Apple services and make all of your devices work together seamlessly.

You can't merge multiple Apple ID account.

Have you forgotten your Apple ID?, check your Apple ID via your email box, see this Apple article: If you forgot your Apple ID

https://support.apple.com/en-us/HT201354                  

OR see -> Having trouble signing in?

https://iforgot.apple.com/password/verify/appleid