Hi Daria, I can imagine how frustrating it is to see your PDFs balloon into gigabyte-sized files just from adding text especially when you’re trying to work efficiently on textbooks.
After editing use Print to PDF instead of saving directly or edit outside Edge by converting to Word or using a lightweight PDF editor like PDF Candy or Smallpdf and finally compress the file with tools such as Smallpdf or PDF24 to keep the size manageable.
Are you mainly adding text annotations or editing the actual PDF content when the file size explodes?
Best regards
Lucky Charm