how i can to unlock my iphone 8 please help

In what way is it "locked", exactly?

If you forgot your passcode, follow the instructions here: If you forgot the passcode for your iPhone, iPad, or iPod touch, or your device is disabled

If it's carrier locked, contact the carrier it's locked to.

If it's activation locked, only the owner of the account used to lock it can remove the lock.

Are you referring to not knowing your passcode? If yes, do this: If you forgot the passcode on your iPhone, or your iPhone is disabled - Apple Support

If you have run into Activation Lock you will need to contact the person who holds the lock.

Only your carrier can remove their lock.

Ask them.