Whether you are creating an envelope on the fly or creating a template to be reused, you have to add fields to your form, even if it is just the signature block and date the document was signed.
Note: If you find you cannot add fields to the documents and templates you create, most likely this is because of your user permission profile.
Responsive mobile views are enabled by default on templates. Please be aware that fields placed in the document may flow differently in a responsive view. Always use the "Recipient Preview" button at the top right to see how your document will look to the end user in both the desktop mode and the responsive mode.
There are many types of fields you can add to a document and different field property configurations.
Field Type Descriptions - 18 standard field types
Add Fields to Documents
Once your envelope includes files, recipients, and messages, you add the fields that instruct your signers to provide their signature, initials, or other information. You add a unique set of signing fields for each recipient.