How can I find my lost phone if I forgot my Apple ID password

Click on this link to read what to do "If you forgot your Apple ID password" --> https://support.apple.com/HT201487

or go directly to this link --> http://iforgot.apple.com/

Also read about "What to do after [or before] you change your Apple ID email address or password" --> https://support.apple.com/HT204071

then:

If your iPhone, iPad, or iPod touch is lost or stolen - Apple Support

You can't. You'll need your Apple ID and password to log into FindMy. Visit iforgot.apple.com