Every reference in your library can hold notes: a private space to record what a paper actually says and why it matters to your work, so the context is there when you come back to cite it.
Why keep notes
A title and abstract rarely capture why you saved a paper. Notes let you jot the finding you’ll cite, the figure you want to compare against, or a caveat about the method — the things you would otherwise forget between filing a source and using it.
Where notes live
Notes attach to the reference itself, alongside its metadata, PDF, and highlights. Open the reference and your notes are right there, so the paper and your thoughts about it stay in one record rather than in a separate document.
Notes and highlights together
Notes pair naturally with PDF highlights: highlight the passage in the source, then summarise it in a note. Between them, a reference becomes a small brief on the paper, not just a citation stub.
Tip: Write the one sentence you would put in your paper about this source. When you cite it later, that sentence is often most of the sentence you need.