How can I model a snug mesh around a complex object? I’m quite new to blender and I’d like to model some attachable camouflage like the one shown in this picture on to a vehicle.

Ideally I’d like it to be made from one mesh over the vehicle. In my head it is essentially a tea cosy for a tank.
Could anyone advise me on how to model it?
I will be using a cycles render engine
Edit: given some of the comments, I thought I'd add another picture that shows the 'tea cosy' after some wear and tear. It is close fitting, 'leafy' fabric camouflage that is attached to a tank.
Edit: So as Batfinger says I missed the coat thing, so it should probably be done with hair particles on a cloth, I'll try to rework my answer.
The first thing that comes to mind is to use a Particle System &gt; Hair, with a leaf as object. Here is what it could give, with the Particle System settings: In Render, choose Render As &gt; Object, and for Instance Object &gt; choose the leaf object.
Give your leaf the same material as the tank hull, on the bottom of the Texture Coordinate node, don't forget to choose Object &gt; Tank so that the leaves will take the color of the area where they are emitted.