When adding an 'Add file' section to a form, this has a 30MB limit.  This is because the uploaded file gets sent with the form submissions via email, and some email queues have a file size limit set on them.

 

For more information on the 'Add file' upload button, see the link below:

https://support.vutu.re/hc/en-us/articles/360020702438-Using-forms-with-InterAction#Add%20file%20upload%20button