Club selection is supported starting with Golf Pad version 15.8 and watch app version 5.3.4.
First, select 'Track shot distances and clubs' in Golf Pad Preferences > Smartwatch sync.
Keep score on the watch as usual. When you add a shot, the app will show the club selection screen. Tap on a club and it`ll be added to your shot.
You can use this feature both in 'standalone' mode or 'connected' mode. See this instruction on how to play in 'standalone' mode: Can I use my Samsung watch in standalone mode, without the phone?