I want to update of my iOS 15 in my iPhone 7. But it does not shows up in my setting

So you don’t see this:

That means that you have a business or school email account on your phone, or it is under MDM (Mobile Device Management) by a business or previous owner who maintains control over updates.

That means that you have a business or school email account on your phone, or it is under MDM (Mobile Device Management) by a business or previous owner who maintains control over updates.

You would need to contact the business IT department to update.

What do you see when you go to Settings/General/Software Update?

my iPhone 7 doesn’t show software update