To find out whether an app works on your phone, look on its listing for the minimum model required. Then compare that with your phone.
Open the app store (App Store on iPhone, Google Play on Android), tap the magnifying glass, type the name of the app, then tap its name. You should see its listing: the page that presents the app, with the Get or Install button.
Scroll down to Compatibility (iPhone) or About this app (Android). You should see a minimum version, for example « iOS 16 or later ».
Find your phone’s version: Settings > General > About (iPhone), or Settings > About phone (Android).
If you don’t see it: a greyed-out or missing Install button often means the device is too old. Updating the phone sometimes solves the problem: Settings > General > Software Update (iPhone), or Settings > System > System update (Android).
Limitation: a very old phone no longer receives updates. Many tools also have a website version, which opens in the browser.
To picture it: it is like an ink cartridge: it only works with certain printer models. The app listing tells you which models are compatible.