Cranks tend be shorter and fatter and have a larger bill or lip. They also tend to have a wider variety of lip or bill shapes. They tend to be deeper diving, usually below 3'. They tend to be used more in lakes.
Jerks tend to be longer and skinnier and have a shorter bill. They tend to have very low variety in bill shape. They tend to ride higher, 3' and up. They tend to be used more in rivers, creeks, and ponds.
Jerks often get called "top waters" even if they dive. This gets them confused with true top waters like poppers, and frogs.
You may have noticed a lot of use of the word "tend", because all of this is fairly malleable and there is a great deal of overlap. If I say jerk baits NEVER have a long teardrop shaped lip then the next post will be someone posting a link to one. If the forage someplace is long and skinny and 12 feet down people will be using a long skinny diving bait with a big lip, whatever you want to call it.