You can choose from a wide array of acceptable file types, including text, image, audio, and video file types, for your submission categories.
1. In the Categories tab of the main navigation bar, click the title of the category you want to update.
2. Open the Form Designer tab.
4. Click the Attached Files field at the bottom of your form. (If you don't see an Attached Files field you can drag one onto your form from the Toolbox on the right.
5. Select your preferred acceptable file types. You can also specify the number of files submitters can upload for each submission (from 1 to 75).
6. Click the Done button on the right side of the field.
7. Click Save Category.
For more information on creating or editing a submission category. read this article.