The 1st use of the tank was in 1916 at the Battle of the Somme, the Mark 1. It wasn't that great, many broke down even until the mark V.
The 1st prototype went 3 mph and many other tanks early on broke down a lot. It's name was "little willie".
Tanks by the end of the war were slow, broke down a lot, but provided support for the troops.
The most revolutionary tank was the FT-17, with a 360 degree rotating turret, which other tanks didn't have. It is the template of many modern designs today.
The 1st tank on tank battle was in 1918.
Hope this helped
