Making Doom 1/2 style game. How could I handle the hand sprite being in front of the camera?

So im currently working on a small doom 1 and 2 type project and I want to put hand sprites (like the ones I have attached) in front of the camera so they can function as weapons. But I'm not sure how to go forward with doing this. Im quite new to unity I only started late last year. How could I achieve this?

 

Personally, I recommend using the unity UI (user interface) system. It will basically do an overlay onto of the camera showing the user interface. If you insert the hand upon a UI image on your canvas and then animate, it will create a similar effect.
Alternately, you can use a quad and parent it to the camera. This will basically create a sprite in a 3d space that will fallow your camera. I strongly do not recommend this method as it can cause visual issues like your hand going into walls if you get too close to them. However, you can use camera stacking which creates another rendering layer on top of the which fixes the issues caused by attaching a quad to your camera.
Hope this helps