Adding models to server so everyone can see/use

i am an admin on a friend’s gmod server and dislike all the models supplied with the vanilla gmod game. my question is as follows:

Q: if a model (garrus) was to be downloaded onto the server (or whatever) will everyone be able to see it / use it?

is there a way to do that? if so what would it be i am friends with the owner so i can have him do anything if he needs to…