I want to make around 10 RC cars for racing. Is there any ready made radio control units that I can buy where I can assign each radio unit to each car and then race with those cars? If so can you tell me where I can get it (website link).

If I have to make it by myself can you tell me which RF modules I need to buy and use?

Thank you

P.S I am new to it and dont have much knowledge on radio control units

If you mean you want one remote to control any of 10 different cars, then yes there are a bunch of them. When you start looking at radios, look at the "Model Memory" spec. That's how many different cars you can have associated with that one remote.

Examples (just type any one of these into the search bar on www.amainhobbies.com):

Spektrum DX3R or DX3S
Airtronics M11X
Futaba 3PM-X
KO Propo EX-1 or EX-10

I am running over 30 rc cars and trucks with just two remote control units (radios). You get an additional receiver (the part that goes in the car) for each rc and then select a new model on the remote (radio) to setup with that particular car. The radios usually let you name each one so you can tell them apart.

Then its a matter if deciding which one you want to run. selecting that one on the radio and running it.