I don't see the restore or update button on my iPhone screen.

to update read Update your iPhone, iPad, or iPod touch - Apple Support

to restore read

Restore your iPhone, iPad, or iPod to factory settings - Apple Support

and or

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

Is this about your forgotten passcode?

In case your iPhone has iOS 15.2 or later installed, follow the steps in this article:

How to reset your iPhone, iPad, or iPod touch when you forgot your passcode - Apple Support

For older iOS versions follow this one, to erase it, using your computer:

If you forgot your iPhone passcode - Apple Support