It is possible to pre-populate a form with WordPress post data using the Post Management integration. The data could be from a page, post or any other custom post type registered in your theme.

To do this:

1. Install and activate the Post Management integration.
2. Click the Form Settings  icon in the top toolbar.
3. Click on the Data tab.
4. Check the Populate Using Action setting.
5. Select Post Management from the Action To Populate From dropdown.
6. Select the the post type you would like to populate data from.
7. Use one of the follow to determine which post to populate from:
   1. Leave it blank to use the Post ID of the post/page the form is shown on.
   2. Enter a post ID (e.g. 123) if you want to literally update that post ID.
   3. To use query string variable, enter: #query_var("post_id"). Example URL: https://yourwebsite.com/page-with-form/?post_id=123
8. Use the Field Mapping, Meta Mapping and Tag Mapping settings to determine which fields, meta and tag (WordPress terms) you would like to populate into which fields of your form. Click the Add  icon to add new mappings.
9. If you have a custom field plugin installed, field mapping options for that plugin will also be shown. Use this to match user custom fields to fields on the form. WS Form is integrated with ACF, ACPT, JetEngine, Metabox, Pods, and Toolset.
10. Click Save.
11. Click Publish if you want the changes to go live immediately.