Word, Google Docs - Pretty much the same deal, depends on the series. Word I use because might as well use it since mom has me paying for it so she can use it cause she doesn't like google docs, and Google Docs when when I'm working on projects where it's not just me doing the writing.
Notepad - Always keep it open for jotting down quick ideas brain storms, quick character jokes/interactions, that I want to work into the story but have not, or have written in another file and are waiting to be merged into the final version of the story. (as well as computer notepad I still use actual notebooks to do this too, for moments I get ideas when I'm not at the computer, then transfer to my notepad on the computer when I am able to)
Google Search - I'm... not great at English, I have low English comprehension level somewhere around grade 6 or 7 I have been told. So when I am having trouble finding or spelling a word I'll throw it into google, it's usually a lot better than word's spellcheck is at trying to figure out what the hell I am trying to write. It doubles in usefulness by giving me meanings of the words and I can see if the word I am trying to use is even the correct word I should be using. Not completely related to writing but I can also get pronunciation, something I almost always get wrong.
Clip Studio Paint - I used to do a combination of Sai, MangaStudio 4 and Photoshop to make my pages, but had a really bad computer crash, and due to a lot of moving around, could no longer find the codes or even the disks for these programs anymore (with the exception of Sai, which was a download, but would also NOT install properly on my new computer and was therefor unusable) I was recommended CLIP by other artists (I drew comics as a job at that point, the longer I didn't draw the longer it would take for me to be paid, so it really important to find a program) with this program I can basically do everything I did in those 3 programs in 1. I still miss a lot of things I could do in photoshop, mostly with text. But I don't miss it enough to pay a subscription fee.