Adobe has no online subscription service for "editing" PDF page content.
Actually PDF is decidedly not a word processing file format. Consequently PDF does not tolerate word processor like "editing".
While the use of Acrobat provides the ability to perform minor touchups such are not equivalent to word processor / page layout editing.
To be able to perform minor touchups to textual content you'd want to use Acrobat.
To "edit" content you need to be using an authoring application (InDesign, FrameMaker, MS Word, NotePad, etc.).
When mastered content is up to snuff in the authoring file output the PDF.
If this PDF still needs work return to the authoring file, edit, output a fresh PDF.
Once you've a good-to-go PDF ship it off for the newsletter.
Be well...