Can you add more apps

You can add apps to the watch directly through the App Store on the watch:

Download apps on your Apple Watch - Apple Support

You can also use the App Store on the connected phone to search for and download apps to the phone. Once you'd done that, you can use the procedure Carol B. outlined to add the apps to your watch.

Yes. To add more apps to your Apple Watch, open the Watch app on your iPhone then scroll down to Available Apps. Select what you want from there.