Most browsers have a way to "bookmark" (save) a web page address (URL) and to create folders labelled with categories into which you can group various "bookmarks".

If that's all too complicated for you, simply create a new file in your favorite text editor, paste the URLs into the page (with notes to remind you what it's about) then save the file.

And please don't say "I'm using a phone". A phone isn't a good research tool. Use a computer. Otherwise, simply use the phone to send the URL to your computer.