I'm trying to unlock my IPhone 12 Pro Max and I need help

If your iPhone has iOS 15.2 or later installed, check out this link→How to reset your iPhone, iPad, or iPod touch when you forgot your passcode - Apple Support. Otherwise:

See this Apple support link→If you forgot the passcode on your iPhone, or your iPhone is disabled - Apple Support

Or watch this companion video ⬇️

After restoring the phone using one of the methods above you can restore your most recent backup.

There is no way to bypass Apple’s theft deterrent feature Activation Lock without the Apple ID and password used to enable it. NONE. So I hope your friend’s memory improves. Or they can use Apple’s password reset feature:If you have forgotten your Apple ID password – Apple Support (UK)

Unless the ‘friend’ prepared it properly before they gave it to you, you will never be able to use it. If your ‘friend’ can’t remember the passcode you are out of luck. Return the iPhone 12 to your friend or recycle it properly.