Unable to share my location with a contact on Find Me

This usually happens when location sharing permissions are mismatched between you and your contacts. Since they can see your location but you can’t see theirs, it means your side of the connection is fine, but theirs hasn’t been fully enabled. 

Network & Privacy Settings

• Both devices need a stable internet connection.
• On their phone: Settings → Privacy & Security → Location Services → Find My should be set to While Using the App.
• If Location Services are off, you won’t see them.

The process shown in the image must be enabled on both devices.

To use Find My and Location Services on an iPhone effectively, both your iPhone and the device you're trying to locate must have an active internet connection. These services rely on internet access to share your location with friends and family and to track the locations of devices, people, and items. Without internet connectivity on either end, the sharing and locating features of Find My and Location Services will not function properly. --> Internet not available WiFi and Cellular … - Apple Community