This has been asked many many times. Please search for the discussions.
I recommend no one use this website. See my review of it here: https://community.adobe.com/t5/Acrobat/how-to-prevent-pdf-files-save-locally-or-forward-the-to-anyon...
In short, the protection it offers is easily overcome and it is not clear who (or what) is behind it, that you're giving access to your sensitive files to...