Here is a list of some really helpful apps for research and note-taking:
Google Drive / Docs (free)
Notion (free for students)
Logseq (free)
Obsidian (free)
Roam Research (Student discount)
Evernote (discount for students)
Apple Notes (free on MacOS and iOS)
Simplenote (free all platforms)
Goodnotes (iPad)
FreeForm (Whiteboard Style app on iOS/MacOs)
Tiddlywiki (free, open source)
Zotero (free, open source)