Enable Merge tag

Hi,

I am trying to redirect a gravity form to another page on submit and at that page I am trying to show one value from the form on the previous page.

This guide seems to be correct and that I’m trying to follow:
https://gravitywiz.com/documentation/gravity-forms-post-content-merge-tags/

However, I don’t have the checkbox “Enable Merge Tag in page content”. How do I enable this or finding a workaround.

Best regards,
Fredrik