PDFs can be used to format anything. So the security measures you take will depend upon the intended purpose of the PDF itself.
Does the PDF contain any personal information? An important work draft? Professional and financial information? In any case, you need to assess what needs to be protected and what doesn't.
Creating a document in PDF, you probably already have a sense of who the file is being sent to. However, ask yourself who the file isn't intended for because this will determine what other precautions you may need to take.
If your document is allowed to be publicly or privately viewed, consider how you want that viewer to use your file. Do you want any information to be edited? Printed? You can set specifications on how much access the user has with the document.
Determining the answers to these questions will help you decide what kind of security your PDFs need. When you have made this determination, consider implementing them using the security features of Able2Extract PDF Converter to create PDF documents that will be safe from tampering.