You control your location sharing, just as your contact controls their own location sharing.
Apple's support document Find friends and share your location with Find My describes how to operate sharing and the options available in the section called Share With People:
- Open the Find My app and select the People tab.
- Select Share My Location or Start Sharing Location.
- Enter the name or phone number of the person you want to share your location with.
- Select Send.
- Choose to share your location for One Hour, Until End of Day, or Share Indefinitely.
- Select OK.
When you share your location with someone, they have the option to share their location back.