how can i reset my iphone 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

And if it is the passcode you have forgot:

Follow the steps in this article:

If you forgot the passcode on your iPhone, or your iPhone is disabled - Apple Support

If you have a backup you can restore it from that

Restore your iPhone, iPad, or iPod touch from a backup - Apple Support

Good luck!