How can you collect feedback about the quality of your service?

If you are talking about a restaurant, when a customer asks for the bill, with it simply place a feedback card with a pen for the customer to fill in. It should be small and not too many questions, otherwise you risk annoying the customer. Ideally you should not have listed more than5 questions you seek the answers to and also leave some blank space where the customer can write critisism, suggestions, recommendations or complaints. This is a simple way of tracking  the quality level of the establisment's performance.

Note the use of client satisfaction, and also the first visit to the client, and finally what is written by the client in the paper notes, which are given to the client to show the extent of dissatisfaction with the public service, but most of the workers in the field of services know very well what is written in the paper notes before they are given to the customer through efficiency the service provided to the customer