Garmin Connect doesn't read data from Apple Health and can't receive any data from Apple Watches, the data sent to Apple Health depends on what options are enabled in Health and what types of data are supported by the connected Garmin device.

If you enable the Sharing option, Apple Health can receive different kind of data from Garmin Connect, find here more informations: https://support.garmin.com/en-US/?faq=lK5FPB9iPF5PXFkIpFlFPA 

To enable the Sharing  option to send the data from Garmin Connect to Apple Health, follow these steps:

• Open Apple Health
• Tap on your Profile Picture (top right corner).
• Tap on Apps
• Tap on StepsApp
• Enable All Categories

Once the Sharing option is enabled, the Health app will only display previously recorded data from up to two weeks prior.

Please contact us via help@steps.app if you need further informations!