I can’t install google photo app in this Device

If your unidentified iPhone model doesn't support iOS 14 or later, obviously you can't download apps (like GooglePhoto) which require that operating system version.

Identify your iPhone model, using these instructions:--> Find the model number of your iPhone, iPad, or iPod touch - Apple Support, then these:--> Identify your iPhone model - Apple Support.

Then take a look at this compatibility list:

If you are experiencing any difficulty with third-party apps then please contact the app developer directly --> How to contact an app developer - Apple Support

Ask the App developer to release the app for lower iOS versions also. Netflix has done it, see the pic below.