Are you asking how to save a file to Acrobat.com? If so, you can log in to cloud.acrobat.com/files using your Adobe ID an password. Once you're logged in, click the cloud icon in the upper-right corner, then navigate to the file that you want to upload and click OK.
If you're in Reader, you can upload to Acrobat.com by choosing Save As, and then clicking Save to Online Account at the bottom of the Save As dialog box.
Please let us know if you have additional questions.