As the browser is by far my most used app, I find that bookmarking the current tab and describing the task with no more than a few words or even as little as a few chars, to be a good way to keep track of what things I need to do soon. For things I would get to later or whenever I feel like it, I’ll put them in Firefox’s “Boookmarks Menu” or “Other Bookmarks” folders, and have lots of folders consisting of Reddit posts and searches about different topics.
I don’t trust myself to remember to check a to-do list, so when I know I want/need to do something later, I just add it to my calendar so I get notified and I can snooze it if I want to delay it but not completely forget.