How is the user's actions checked by the cheat service?

Question

Computer networks

Vobschem interested in such a phenomenon, or rather how it is implemented.
For example, there is a service for cheating likes or friends in any social network, this service sends the one who puts likes on the link, the user puts likes and the service accrues points to him.
The question is: how does it check whether it was installed or not, as well as how it is implemented and in what language, if possible, then a link where to read about it