For the most part, your squadmates fight using their own judgment. Their powers and specific weapon attacks cannot be directly managed; however, you can give them orders for positioning and target focusing.
Focus Fire: Highlight an enemy with your soft-aim target (indicated by the large rectangular brackets around the enemy), and press the Left/Right Squadmate Orders command to have your squadmate direct their attention to your target. This is useful for prioritizing and eliminating high-threat targets on the battlefield.
Take Cover: Aim your reticle at a cover-giving object (e.g., blast shields and wall corners) to have your squadmate safely establish a defensive posture. Using this tactic meticulously is vital on higher difficulty settings against enemies like the Anointed.
Regroup/Defend Ryder: Holding the Left/Right Squadmate Orders (or Both Squadmate Orders) command calls one or both of your squadmates back to your position to fight with you. This is particularly useful if they’re caught out of position and in danger of being knocked unconscious, in case you need to revive them. Get accustomed to this command for difficult encounters.