How to upload a file for view into a form?

I'm not sure if I understand your query correctly. Do you want to allow the users to upload a file using the form? If so, you may add the File upload field to your form so that the files can uploaded using it.

You can also allow to upload multiple files at once by using the option Allow Multiple from the tool bar or Upload field properties.

Hope this information helps! Let us know if you are referring to something different. We will be happy to help.