At least 20 states allow their residents to demand that data brokers delete their personal data, but typically consumers must file requests with individual data brokers. California has a centralized portal for requesting such opt-outs, at privacy.ca.gov/drop/. People also can change their mobile device settings to prevent tracking:

To turn off location tracking on an iPhone: 

Go to “Settings” and enter “Location” into the search bar.

Click “Location Services.”

To turn off location tracking completely, click the “Location Services” toggle switch at the top of the screen to the off position.

Or, from the same “Location Services” screen, navigate through individual apps to turn off location access app by app.

To stop data brokers from tracking you:

Go to “Privacy & Security,” then “Tracking.”

Turn off “Allow Apps to Request to Track.”

To turn off location tracking on an Android:

Open the “Settings” app.

Scroll down and tap “Location.”

To turn off location tracking completely, toggle the switch next to the tab to the off position.

Click the “Close” button if given the option to turn on location again.

Or, from the same location settings screen, navigate through individual apps to turn off location access app by app.