Mutual agreement changes the practical situation, but it does not make every tracking method appropriate. The safest arrangement is visible, revocable location sharing where both adults know which service is running and can turn it off.
Use Apple Find My or Google Maps Location Sharing first. Both show that sharing is active and are easier to stop than a monitoring profile installed deep in a phone’s settings. If you want to send a one-time location request rather than maintain continuous tracking, Scannero sends the recipient a message and shares the location only after they open and approve the request. Buy Scannero →
Before switching anything on, agree in writing on the purpose, the start and end date, whether location history may be stored, and whether either person may stop without punishment. Do not add message access, microphone recording, hidden GPS tags, or account-password sharing to a location agreement.
Local privacy and recording laws still apply. If tracking is connected to divorce, custody, a protection order, or a workplace device, get advice from a qualified professional in your jurisdiction before collecting data.