We the members of this forum are outsiders and we do not know the nature of the work that your employees do at the site. What is the nature of your industry? Why employees are required to work at the client site?
If you want to measure the quality of the work rendered by the employees working at the site, then I recommend you asking this questions the Managers (from the client side) to whom these employees report. Various managers will give various replies. You may compile the replies and make a template.
Secondly, you may talk to the HR of the client to know how to measure the work.
Thirdly, suppose if the employees were to work at your company premises then to whom they would have reported and how the reporting manager would have measured the work of those employees? Therefore, ask this question to someone from your own company also.
Lastly, about maintaining anonymity while uploading your post. This type of query does not merit anonymity. Facility of making post anonymous is provided to the members who wish to write something negative about their workplace or company. It could be workplace harassment, bullying etc. Your post does not come under that category. Therefore, making your anonymous was misplaced action. Please use this facility sparingly.
1st May 2018 From India, Bangalore
You would be in a better position to develop one on the basis of what are the deliverables to the client by your resource. The parameters of the client feedback form are intrinsically linked to the deliverable.
2nd May 2018 From India, Mumbai