Programs for PDFPortable Document Format (PDF) is an electronic document format developed by Adobe. Accordingly, this company also offers programs for working with PDF, but, of course, not only this company.
There are quite a few programs for viewing PDF and they are all free - if you do not like Adobe Reader, you can find a dozen other offers.
It's not that simple with PDF editing. Adobe offers its utility for money, and most other manufacturers do the same. Nevertheless, free PDF editor programs also exist, although, as a rule, with some restrictions. PDF is a peculiar format - so, very few PDF editors can provide the ability to change the text as a regular text editor. Although, in many paid programs there is such an opportunity.
Perhaps, for editing PDF files it will be easier not to look for a special editor, but to convert PDF, for example, into MS Word. To do this, you can use online services, for example:
Another conversion option is to use a text recognition program - OCR (which can also be found free) and end up with the same text file.