Editing original and save as original

Hi, I'm new to Adobe Acrobat Pro that I have an original document that I have all rights to. When I make a change and click save, it doesn't save the changes.  It makes it like a copy so when I reopen the original ot doesn't save changes.  The files it makes have my edits but the text boxes are all different and hard to edit. How do I edit my origins and save edits as original so formatting stays the same.  It just won't save the edits unless I save as.  But then it's hard to edit and this file will be edited often and for years to come.  Thank you.