On Windows 11, you'll find a new Sticky Notes, which is essentially a redesigned version integrated within the OneNote app.

For quick reminders and can’t-miss memos, sticky notes are effective tools, and I’d argue that the simplicity of the sticky note is its best attribute. But the ease behind propping up sticky notes ...

Simple Sticky Notes lets you create sticky notes on your PC.They’re just like the Post-it notes that litter people’soffices–but more private and not so unsightly. It’s incrediblyeasy to create them.