tax forms

Hey guys, I need to get some tax forms (W-9 and W-4) filled out and sent by EOD. I'm trying to avoid downloading heavy PDF editors or paying for Acrobat just for this. I found a site called convert2.info that seems to do it in the browser. Before I put my info in, has anyone here used it? Is it reliable for government forms?

Not sure if this is wortha shot, but i think you can open a pdf in a browser window, and inspect element to change things, then take a screenshot? Only thing i can think of that you won't find yourself down a rabbit hole of fake sites, and malware