What do you mean by "matching?" Paint "matching" is generally a term for improving match of a paint that already is the right "code" and just needs to be "refined." This is used in collision repair every day when you put a new fender on a 2015 Lexus to make the color as close as possible to the adjacent panels.
If you are painting a "complete" where the whole car is being painted, it's not so critical of course.
If this is what you are doing "matching" isn't an issue (realistically) you simply give them the paint code on your car and get the paint mixed. This code could have "alternates" if you working with a late model car, but if it's not a late model there isn't much to think about, the code is all you need.
Now, if you want to paint it a different color than original, find a car you like the color of and get the paint code. I remember years ago painting my truck and a friends mom bought a new Chevy and the second I saw it, I knew that was the color I wanted. I opened the door of her new car, got the code and that was all there was to it.
So you can order something on line with that code and your color will be on your doorstep with the UPS man.
Does this answer your questions?