Adding file upload field on the form

is it possible to have someone attach documents to the application if I ask for a letter of reference from them?

Hi there,

If I understand you correctly, you want to have a field where your users can upload a file like a resume or letter right?

Use the "File Upload" under form tools. You can allow multiple uploads, change the file size limit and allow selected file extensions. 

Hope this helps. Let us know if you need further assistance.

Thank you.