Makeup artists go to work. For example, if you go to work in an advertising company or a photography company, do you prepare cosmetics and tools yourself or the company?

You can tell this to the company. Some companies bring their own cosmetics, so most of them will get a certain commission, and some will let them use the cosmetics prepared by the company. There are all kinds, but most makeup artists like to use their own, because it is convenient, but some companies are afraid of customer allergies and so on, and have requirements for some makeup!