Create Text Field in Form

Are you hoping for a comment-type box? You could create a field that holds comments and a campaign that appends comments to some other notes field each time it is updated.

You can add whatever fields you want to the form using a Rich Text area (or add them in the browser using JavaScript), but ultimately the data needs to be stored in field(s) that exist in your Marketo instance. 

So use checkboxes, dropdowns, or other widgets for user interaction, but the data is expected to be saved on the lead record. In your case if you want a textarea, you should create that field in Marketo: something like LastProposalDescription.

Hi Chrissy, you will need to create a field to use in your form. If this is a field that you will only use one-time on your form, consider creating a few fields for this type of one-time use. In our instance I have set 4 fields (Marketing 1-4) that are synced to SFDC and 3 fields that are Marketo only (Response 1-3). These fields can be used in forms to capture very specific information (mostly for events) that doesn't need to be stored for an extended period or reported on. You can customize each field in the form to exactly your needs such as a date fields, drop down or large text area. Ex. Marketing 1 can be a Select field for "Please select your meal" with options of Fish, Chicken, Beef.