Adobe Acrobat Reader DC is a free app. So you cannot purchase it. Do you mean Adobe Acrobat DC?
Did you pay for the subscription or for the desktop app (full or upgrade)? Please take a look at your receipt to find the exact name of subscription/app that you purchased.
Which type of app are you using to convert a document to PDF?
(a) a mobile app on an iPad/iPhone or an Android tablet/phone
(b) a desktop app on a Windows or Mac computer
Sorry for all these confusing names. Once we know which app you have, we can move this discussion to the right forum for your question.