You can add a private note to any user on Discord by following one of these steps:
Option 1: Right-click on the user's name and select "Add Note" from the dropdown menu.
Option 2: Right-click on the user's name, click "Profile", and you’ll see the "Note" field where you can type and save your note.
To check your saved notes later, follow the same steps as described above or look for the 📝 paper emoji icon on the user’s profile — click it to view or edit your private note.
These private notes are only visible to you and can help you remember things about the person you’re chatting with, such as their preferences, past conversations, or important details.