The documentation for versions 2.21 and older can be found here.
Currently, thirteen field types exist.
Those field types are:
Date input (old)
Date input (new)
Retrieved from LDAP
The select field allows users to pick a single value out of a drop down menu.
In the section Field options, you can add options to the dropdown menu.
In the left field, enter the name of the option (for example: "Yes, I agree to be photographed.").
Then, click on the + button.
To re-order the options, click on the six dots button to the left of an option and re-position it via drag & drop. To delete an option, click on the delete button.
Link to this page: https://seibert.biz/fieldtypeselect