Linux is about protecting your freedom as a pc user. It means the software should always work for you, never against you, and you should have the right to inspect the code, modify it at will, and even sell it on or give it away for free
There are no licence fees, no tie in, and it runs faster on your pc then windows. It doesn’t spy on your nor force updates on you.
It should run on most computers but occasionally you may have to install additional WiFi or graphics card drivers but it’s not that common anymore.
You should definitely test it first, and try do everything you do on Windows, on Linux. To do this you can either install it alongside Windows or on a separate test pc or Intel it in a virtual machine on your pc
You can also use a live usb which lets you see it in action running off a usb stick but you can’t install additional software so it’s a limited experience.
I unequivocally recommend Linux Mint over any other Linux. I’ve seen the other comments but this is by far the best best Linux distro and the one you’ll feel most comfortable on. There are other advantages as well but you’ll learn that.
In both cases you’ll need to download the deb file to install it. Deb files are like exe but for Debian and Ubuntu based Linux, think Mint is. They are the most widely available format.
I wouldn’t bother with the built in Libre Office as it’s not quite there yet. OnlyOffice can also do some PDF handling as well. You typically won’t find free PDF software for Linux as it’s proprietary software and companies like OnlyOffice likely pay Adobe some licencing fees to offer PDF edit functionality.
It might sound difficult but it’s not, especially if you enjoy computers. If not, ask an IT or nerd friend you might have for help.