Yeah, unfortunately voice commands on Apple products aren't quite as robust as we need! You can do a teeny bit more than just dictation- like editing a bit, which you can check out here:

https://support.apple.com/en-us/HT203085

Windows has a much more robust speech recognition system built in- it's honestly pretty great! 

https://video.search.yahoo.com/search/video?fr=tightropetb&p=windows+speech+recognition#id=3&vid=ac8d1d76e91e3ce502810efb1c41e7e3&action=click

You can always add the Dragon Naturally Speaking software to a Mac to build up what commands you can do with your voice, but if a user is super-high tech, maybe just double check with the support line that it will be able to do everything they need. For instance, I had a user who was having some trouble with some Excel commands in the Mac version. 

http://www.nuancesoftwarestore.com/dragon-professional-individual-mac/