How do I put on trigger enter and exit inside update

I made a trigger/collider and made a capsule follow the player whenever it walked inside the collider, I used the on trigger enter function(I’m using c#) and on trigger exit to do it. It only happens once, so when the capsule reaches where the player initially entered then stops, which tells me it needs to happen every frame. I can’t put the ontriggerenter and ontriggerexit inside the update function it gives me lots of errors help please!

try to use OnTriggerStay()

it 'll work until you triggered out.