Single Latin is a single set of pattern dance, generally more women's single, now the professional Latin competitions, such as provincial and municipal championships have set up a women's single entry, it is a flexible dance, generally less difficult than the double, and fewer patterns, so it is very much emphasis on the basic steps.
Double Latin is also interspersed with routines, but there are more patterns, because men and women are paired up, so it is very rich in realizability. Generally speaking, the competition is in the form of double Latin. It is on the premise of emphasizing the basic skills, the contestant's dance expression put forward higher requirements.
In addition, there are forms such as Group Latin, which is a collective Latin of at least 16 people.
I hope this helps you!