If your transmission fluid is leaking and you have a concrete driveway you should notice what looks to be a red looking fluid and sometimes it may have a burnt smell to it.
Safely jack up your car and place it on jack stands for safety and check around the transmission pan and gasket to see if transmission fluid is leaking from it.
Transmission fluid can also be coming from the front or rear seal of your transmission.
If it's the front or rear transmission seal on the car then it can be costly to fix because the front transmission seal requires pulling the engine from the transmission.