In order to receive menstrual cycle messages, you'll need to connect your tracking apps to Apple Health and share this data with Quin.
Many apps can be connected to Apple Health in the setting or sharing tabs. See below for how to connect some popular cycle tracking apps to Health.
Go to your profile - Settings - The Health App - Connect to the Health App
Go to your profile - Settings - Apps and devices - Apple Health Connect - Health App Integration
Go to settings - Apple Health - Sync to Apple Health
To manually give Quin access to Menstruation on your iPhone:
Open Apple Health
Tap on 'Sharing'
Tap on 'Quin'
Ensure 'Menstruation' is switched on in the list
That's it! Quin will now sync your menstrual cycle.