I do not want to joint all the mesh parts , because I am afraid to lose their own UVs map , (I see some post to not loose uv of every single objects) but I am not user well how to do, by the way, I am asking a punctual asking, can I rig differents pieces of the mesh ? (boots, pants , head, jacket, hand,eyes) what about the vertex weith ? (I am going to use riggify addon).
Yes you can: Actually the armature is a modifier that creates relationship between a bone and a vertex group with the same exact name. If a mesh receives form an armature a request to move a non existing vertex group, it simply ignores the instruction. So you will have to add an armature modifier to every mesh and create as many vertex groups as bones related with that part of the mesh. You will have to manually assign weights.
For the main part of the armature you can select the relative mesh, select the armature press Ctrl+P and choose "with empty groups"; this procedure will automatically create a vertex group for every bone of the armature marked as "deform", ready to be weighted (you can then delete the unnecessary vertex groups).