Passing data from a from to another using POST data on thank you page

How do I do the above?

Hello HRServicesUK,

If you want to pass input data form one field to another, why do you want to do that using POST data. You may like to take advantage of our "URL Parameter" feature to achieve your requirement. Please take a look at the following thread where I have explained this in step by step:  http://www.jotform.com/answers/396268 

If you still want to populate your second form using POST data, you may like to check the following guide for another step by step guide on how to populate your form fields with the value of another form field using POST method:  https://www.jotform.com/help/213-Send-POST-Data-From-JotForm-Using-PHP-in-Custom-Thank-You-Page 

Do try it out and get back to us if you have any questions.

Thank you!