Okay, James.
You’ll need her iPhone.
- Go to Settings > [Her Apple ID Name] > Find My.
- Make sure “Share My Location” is enabled.
- Open the Find My app.
- Tap the “People” tab, then the “+” icon.
- Choose “Share My Location.”
- Enter your contact details. Select “Share Indefinitely.”
She can see who she’s sharing location with if she checks the Find My app.