On the iPad, you can work on your PDFs in either a note-taking app, PDF reader or PDF Editor. Each app category has unique capabilities that set it apart from the others.
Abode Acrobat Reader is a PDF reader by Adobe Inc. On the iPad, it is available to download for free but has in-app purchases for pro features.
PDFelement is a PDF editor by Wondershare Technology Group Co.,LTD. It has a complex pricing structure system for individuals, teams, education and bundles for different operating system combinations.