Adobe Reader is an essential program because whoever more or less all of us have ever received a PDF document.
This program allows you to open this type of documents but not edit them, for it you will need a full and paid version of the program. But to be able to access catalogues, books or other documents in PDF format is all you need.
This program, in its Lite version, is a reduced and compressed version that does not include as many extras as other versions but in exchange it is a light and very agile program. Essential if you do not have any program capable of reading PDF files.