Prefilling or pre-populating Grav Form fields is not an out of the box thing.
To make the use of dynamic fields and function calls (see documentation) easier I’ve created a new plugin, the Form Prefiller Plugin.
It is a first release and thus will not yet show up via GPM. Therefor you need to manually download and install te plugin for now.
Issues may be reported in the GitHub repository.
Please let me know whether you think it’s useful or not.
Not a reply but an announcement instead. The Form Prefiller Plugin has had it’s first public non testing release and will be available in the GPM soon I hope.
A new feature is the ability to profile fields with values as a result of processing a custom Twig template.
Again, any issues, wishes and suggestions can be best posted as issues in the repository. For questions this might be the most suitable place.