Repair stations

Repair stations might be scatter around the map if your vehicle it's damage or out of ammo, you can bring it to one of these repair stations where the vehicle will me immediately refill it's ammo and slowly be repaired when standing still. (Notice: this only works for land vehicles, airplanes have a completely different repair station usually situated in the sky)

Repair kits

All tank crews and enginnears have at their disposal repair kits, repair kits are often used when a vehicle it's still operative but their tracks and/or wheels have been destroyed, in that chase someone has to use a repair kit on the damage vehicle for it to be repaired. To repair a vehicle with a repair kit you must first approach the vehicle (tip: if it is too dangerous it might be better to not approach the vehicle as it might explode) after that hold the "F" key (this is customizable in the settings) and while holding "F" you should see the option to repair the vehicle, a short animation will play after which the vehicle will be repair'd. Note that you can technically repair the vehicle as many times as neccesary as long it doesn't recieve fatal damage, but each soldier usually only carries 1 repair kit so use it wisely.