How to set passcode on iPhone 13 Pro Max

Hi Nanalana2,

Welcome to the Apple (user-to-user) Community!

Re: "I need to change my 6 digit passcode. On my iPhone 13 Pro Help"

You can go to Settings > Passcode

Choose the option: Change Passcode:

Enter a new six-digit passcode. (Or tap Passcode Options to switch to a four-digit numeric code, a custom numeric code, or a custom alphanumeric code.)

from: Use a passcode with your iPhone, iPad, or iPod touch - Apple Support

All the best :-)