Document Sources let you associate a document (or any Rem) with the materials you're learning from — whether that's a PDF you've uploaded to RemNote, a web page, a YouTube video, or another Rem. This way, you'll always know where your notes came from and can quickly return to the original material when needed. You can add as many sources as you want.

At the top of any document or Rem that you've zoomed into, click the Add Source button. This opens the Add Source menu, which has three tabs: Add Source, Link Source, and Record.

Alternatively, if you prefer to use the keyboard, click on the document title and type /source or /isrc to quickly open the source menu.

The Add Source tab lets you upload files directly from your computer. You can drag and drop files into the upload area or click choose files to browse your computer. RemNote supports a wide range of file types, including PDFs, Word documents, PowerPoint presentations, ePub ebooks, Excel spreadsheets, and more. See Supported File Types for Annotation for the full list.

You can also paste a YouTube, PDF, or web URL into the URL field at the bottom of the tab. This is handy for linking a YouTube lecture, an online PDF, or a web article directly to your document.

The Link Source tab lets you connect sources that are already in your Knowledge Base. Use it to link an already-uploaded file or an existing Rem to the current document. This is useful when you want to associate notes across different documents without duplicating content.

The Record tab allows you to directly record audio, such as a live lecture, generate a transcription, and attach it as a source to your document.

To remove a source, click the Add Source button to open the source menu. You'll see your existing sources listed at the top. Click the trash bin icon next to the source you want to remove.

So far, we’ve discussed adding sources to a document or Rem that you’ve zoomed in to. But actually, you can add a source to any Rem at all, even if you’re not zoomed in to it: just type /source on that Rem. The source will appear underneath the Rem and before any children it has.

A source attached to a document A, that points at a document B that contains flashcards, will cause the flashcards in document B to be included when you practice cards from within document A. This can be a convenient way to practice the flashcards of several documents with related topics at once.