Is there a limit to how many files my customers can attach to a ticket through the web form?
Customers that are not logged in can attach up to five files to a ticket. Authenticated users can attach up to ten. The web form utilizes linked attachments and as such the size limitations for a single file is 50 MB, as described in this section: Attachment size limitations.
This means that in a single comment update or ticket submission through the web form, an unauthenticated user can send up to 250MB in the form of five 50MB attachments, while authenticated users can send up to 500MB in the form of ten 50MB attachments.
For related information, see this article: Can I change the attachment size limit in ticket comments?