what programs and tools do you guys use for college?

i got some peer review back for my analysis paper, and they commented on my incorrect usage of its and it's. this prompted me to go searching for tools that are useful when writing, and there's no better place to find them than asking people on the internet!

i use languagetool and zotero currently, which are both amazing programs. i just want to know if i can "maximize" my paper writing expertise.

let me know what you guys use! i like using open-source software, but i want to know everything!