To put it simply, an executive golf course is a shorter version of a regular golf course. Executive golf courses still have 9-holes and 18-holes, but they require fewer shots to get around.
Golfers playing on an executive golf course will hit fewer shots and travel a much shorter distance. As a result, a round of golf on an executive golf course can be completed much more quickly than on a regular course.
Most executive golf courses consist mostly of par 3 holes. However, they do also feature some par 4 and par 5 holes too. The par 4s and par 5s on this type of course will still be a lot shorter than par 4s and par 5s on a regular course though.
More often than not, executive golf courses are part of a bigger golf club.