Notifications are sent automatically based on your note time schedule.
On Android: open Settings → Notifications:
- Screen Alert: Show visual reminders
- Audio Alert: Play notification sound
The sound and vibration themselves follow Android's notification settings for 1krNote (Settings → Apps → 1krNote → Notifications).
On iPhone: reminders follow the iPhone's settings for 1krNote: Settings → Notifications → 1krNote (sounds, banners, lock screen).
When reminders come, and what to do if they don't: see "Reminders don't arrive".