There are several excellent note-taking tools for the Mac and iOS, including Microsoft's OneNote, but Evernote puts them all in the shade. While the premium version offers some excellent and powerful features, the free version is ideal for most people’s needs.
You can create multiple notebooks and 'stack' them to keep them organised. Notebooks can also be shared, and you can even chat to colleagues from within the app.
Adding notes from a browser on iOS is done through Share Sheets, and on the Mac through the Evernote Clipper. The Clipper allows you to grab a URL, a full page, or a simplified version of the page which saves just the content you want.
Notes created in the app can be text, images, or audio recordings and, because it's scriptable, you can create Automator actions to, for example, Print PDFs directly to Evernote.
Whether you're researching an essay, planning a new kitchen, or managing a small project, Evernote is a terrific tool.
The constant nudges towards upgrading to Premium are a little annoying, but they're a small price to pay for such a useful app.