Follow this guide to modify the naming convention on the files your clients upload, that are converted to PDF within the invites.
To begin, click the gear icon in the bottom left corner and select Preferences from the menu that appears. If you've set up cloud sync, you can also enable renaming of downloaded PDFs by selecting the radio button on the naming convention screen.
Here, you can customize the date and contact name format, add a custom field, and choose which fields to include or hide in the file name by clicking the eye icons next to each field.
Be sure to click Save Settings when you're finished.