is there a way to add apps from the iphone to an apple watch

The apps in question have to support being added to your watch. If they don’t you can’t. Simply open the Watch app on your iPhone and scroll down to the Available Apps section, then click the INSTALL button of the ones you want added to your watch.

You may only do that if the app's developer intended for you to be able to do that and developed a watch version of the app.

If an app on your iPhone can be installed on your watch it will appear in the iPhone's Watch app in the My Watch tab towards the bottom.

M1 Mac mini, macOS 14.2;  Watch, series 7 GPS/cellular, watchOS 10.2; iPad Pro 2nd Gen, iPadOS 16.7.3; iPhone 12 Pro, iOS 17.2; TV 4th Gen, tvOS 17.2; HomePods, audioOS 17.2 and Airport Express w/ Airplay 2