Four days, each half of the body twice a week. The intermediate default.
The plan most people with four days should run. The two lower days lead with the squat and the hinge, the two upper days with a press and a pull. So every muscle gets hit two different ways each week. Run it on 2-4 days. Fewer days just means each lift comes back less often. New to training? That's fine, every lift starts with a measurement. How it decides explains every rule the app follows.
On three days, Full Body does the same thing in two sessions. On six, Push/Pull/Legs has more volume than anything else here. If you want strength on the four lifts more than size, GZCLP+ runs the same days.
Push/Pull/Legs if six days fit and four leave you fresh. A Glutes template if one body part is the point.