PDFs (portable document format) are files that, for the most part, cannot be edited. The text and images are "flattened". So, unless you purchase a tool such as Adobe Acrobat Pro DC, your only other option is an "Add To" editing tool. I call them a "Add Too" tools, because that's what you do to the document. You ADD text, cover unwanted text, add images, line drawings, highlighting tools, etc. but cannot remove or edit existing items.
My favorite "Add Too" by far is Doc Hub! I have used it with 6th and 7th grade students and found it very easy for them to manipulate. Students can access and sign up for it directly through their Google Drive. They can also share their work with you and collaborate with other students just like a Google doc. As a teacher, you have the option to add annotations BEFORE assigning it to students in Google Classroom and the ability to leave comments as they work.
Doc Hub also offers the option to add an electronic signature to documents. I have used it for scholarship applications and my daughter has used it for college club and job applications as well.
NOTE: Need to SPLIT A PDF? Use a Chrome Extension such as Split PDF to break your PDF apart in to separate pages.
NOTE: Need to SPLIT A PDF? Use a Chrome Extension such as Split PDF to break your PDF apart in to separate pages.