Unless you are very quick and efficient with manual focus, I would recommend setting your camera to autofocus. For the vast majority of occasions, this will work fine and give you sharp photos. If you find that it isn’t quite right, then switch to manual focus.
If your camera has various focus point when you look through the viewfinder, test these out to see if there are any that don’t focus as sharply as others. The outer ones will sometimes not focus as sharply as the centre ones.
The only time that I always use manual focus is when my camera is mounted on a tripod. I can zoom into specific sections and make sure that it is as focused as I want it to be.