I have forgot my Apple ID password and I want to change it and my old phone number

See: If you forgot your Apple ID password https://support.apple.com/en-us/HT201487

You also can use Having trouble signing in/iForgot  https://iforgot.apple.com/password/verify/appleid 

You also may need to see If you forgot the answers to your Apple ID security questions https://support.apple.com/en-us/HT201485

Go here if you need additional support Apple

telephone support https://getsupport.apple.com/?caller=kbase&PGF=PGF63005&category_id=SC0245&symptom_id=23362

For worldwide Apple ID support go here https://support.apple.com/en-us/HT204169

If you want to change the number associated with your ID, you need to change the number on your Apple ID. After the change, allow up to 24 hours for the change to sync. Before trying to make the change, sign out of Messages/FaceTime.

Apple ID - Manage