How would I include a hidden database field, that is automatically populated, in a sign up form? For excample, if I want to add the field "source" and include a hidden field on a form inserting the form name or other identifier?
Hey there! There is a bit of work to accomplish this, but you could definitely do it accessing Emma’s API and setting up a custom form while configuring those fields. Emma's API allows you to connect any form hosted on your site directly to your Emma audience groups. You decide which information (name, email and any other fields you store in your Emma account) gets added, and you specify the group(s) to which new people will be added. Each time someone hits 'submit' on your form, the appropriate information gets passed automatically and immediately to Emma.
If you decide to do it, you'll go to your account settings and click the API key tab to generate the API key. You can check out the calls and help documentation here You'll want to carefully look over the sample documentation to make sure it's within your skill-set because support is not provided for this feature.
To get you started though you’ll want to pay attention to these two particular sections for what you’re wanting to accomplish. Signup calls and Member calls
Hopefully this helps, but please let me know if I can assist further.