I forgot my phone password

See -> Change your Apple ID password -> Change your Apple ID password - Apple Support

Then see this Apple article: What to do after you change your Apple ID or password

What to do after you change your Apple ID or password - Apple Support

BTW:

You are sign in here .  .  .  with your Apple ID & Password.

Your Apple ID is the personal account you use with all Apple products and services. It includes the email address and password you use to sign in, as well as the contact, payment, and security details that you use with Apple.

You can’t merge multiple Apple ID accounts.

See -> Sign in with your Apple ID -> Sign in with your Apple ID - Apple Support