Tigers were usually employed in separate heavy tank battalions (schwere Panzer-Abteilung) under army command. These battalions would be deployed to critical sectors, either for breakthrough operations or, more typically, counter-attacks.
The Tiger was originally designed to be an offensive breakthrough weapon, but by the time it went into action, the military situation had changed dramatically, and its main use was on the defensive, as a mobile anti-tank and infantry gun support weapon. Tactically, this also meant moving the Tiger units constantly to parry breakthroughs, causing excessive mechanical wear. As a result, there are almost no instances where a Tiger battalion went into combat at anything close to full strength.