If you require a document to be attached to an online form, e.g. a CV or Birth Certificate, you can do this by adding a field type called Document.
First, click Add Question at the bottom of your form.
Next, select Custom Field and Document from the drop-down options. Click Save once done.
The field will automatically be named Document. Change this to your desired field name.
The person completing the form selects Choose File, browses their device and selects the file to upload.