Are you able to upload a MP4 Video File (VLC) to a form/template?

If you mean to accept MP4 submission, yes, it's possible.

Guide to create the upload form: https://www.jotform.com/help/332-How-to-Create-File-Upload-Forms.

Guide to add a new file extension: https://www.jotform.com/help/29-how-to-change-the-allowed-file-types-in-the-upload-field.

Thanks