I purchased Acrobat DC subscription. I want to protect my PDF, but I do not get the option.

I purchased Acrobat DC subscription. I want to protect my PDF file.

When I open the document (signed into Adobe account). I do not see the option "Protect" in the sidebar. I click on "More Toole" and the "Protect" option is still disabled and when I click on it, it will direct me to the page to buy a subscription.