How to make different poses while holding a tool?

How do I make poses while holding a tool? Example: Player holds a suitcase and instead of the arm facing forward, how do we make it stay in the bottom and hold the suitcase like how a normal human would do?

There are ways you could do that. You could use cFrame, place CFrame variables in a Local or just a regular script. Moreover you could also use a animation inside a Local script, the type guns use to play idle animation. But if you want more natural feeling, I recommend using CFrame.