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Outlook notes don’t automatically expand to show all of the text. You can easily make a note larger if needed by hovering your mouse near a corner or edge, clicking the arrow-shaped grab handle, and 
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dragging it to your desired size. However, if you typically jot down large notes, are using a supersized font, or just want a different default size, you can customize the note size in the Notes Appearance dialog; choose from Small, Medium or Large. When your default note settings suit you, click OK to apply them to all of your new Outlook notes.