How to Add Certificate Number under Google Forms to Google Docs - Create Certificates

Dear All,

I have Created a Work flow when user submits the details on google Form he will get the certificate on his email id. I want to add unique certificate number on every form submission and that should be printed on Certificate as well. Currently i have given that option in the Google Form and i am asking participants to mention the same bu ideally certificate number should be generated from my side. How can i add unique certificate number in the certificates to be sent please suggest.

Use Number Formatter -> Counter to increase the Number value and then Concate that counter value with Text , e.g. CERT:

Here is an example,