Official comment
In ONTRAPORT's ONTRApages it is fairly easy; select the button and then the link icon, select ONTRAPORT Hosted File, then Select File. You can then upload a file from your computer or select a file you have uploaded previously:
Note, for ONTRApages accounts, you must host the file yourself and provide the download link as the URL. You can host the file on your website, or in a file hosting service such as Dropbox or Google Drive (just make sure the permissions are set correctly for your customers to be able to download the file).
For Legacy Landing Pages in ONTRAPORT, first upload the file into the File Manager. To find the File Manager, click your email address at the top right, then select Administration. Select File Manager. After you have uploaded your file, click on the name of the file to show the Download Link. Use this link as the URL for your button:
