Animation implementation in AnimGraph

Do I need to put every animation in AnimGraph?

I already put idle and walk in my State machine ( Idle->Walk->Idle ) but I have other animations interact with object i.e PickUp1, Pick2, Touch

Should put other animation in the state machine too?
Idle-> PickUp1 → Idle |
Idle-> PickUp2 ->Idle |
Idle->Touch->Idle

You can certainly add as many states as you want. For your pickup state, you could transition from both idle and walk to a pickup.

Another very useful tool for one off animations is the Montage. Animation Montage | Unreal Engine Documentation

Generally speaking, the montage is best for one-off animation that can be triggered from multiple states.

But there are pros and cons to both approaches.

Do I need to put the animation in state machine for the animation montage too? Or just making the anim montage is enough?