I have a few questions
1) When attacking do you have to issue a command to any companion creatures to attack
2) Do you have to issue the command every turn
3) Does issuing said command(s) take your full action
4) Do any of these rules differ if it is a mount you are riding

— Kellender (@Kellender3) October 10, 2019

There are no general rules in D&D for commanding a companion creature. A creature either works like any other NPC/monster or follows special rules. For example, the find familiar spell gives you a companion and explains how to use the familiar. #DnD https://t.co/5hn1fN1qD8

— Jeremy Crawford (@JeremyECrawford) October 10, 2019