Please give me the latest update of iPhone 7s.

Sorry, but the built in hardware of your iPhone 7 or 7Plus limits the iOS software version which can be installed to the latest version of iOS 15.

To be able to install newer iOS versions, you will have to buy a newer iPhone.

iOS 16 and iPadOS 16 are compatible with these devices - Apple Support

To install iOS 26 and iOS 27, you will need at least an iPhone 11:

iPhone models compatible with iOS 26 - Apple Support