use method=post to transfer values from one form to another

I’m trying to post value from one form to another in wordpress, but can not.

What I have is two custom page templates, with html forms on them. I want to pass, the data from the form on page A, to the more complex form on page B.

I`ve tried using https://thewordpresswarrior.com/616/passing-variables-via-url,but thats not working.