United is offering 1,000 Free United MileagePlus Miles by simply enrolling your United Visa Rewards Card in their United MileagePlus X App (Google Play link or ITunes.

Mileage Plus X app

The United MileagePlus X App “features a rich selection of shopping, dining, and exclusive Cardmembers offers. Search for your favorite restaurants and retailers to see all the current offers available across the entire app and watch your miles pile up”.

This offer is good through March 31, 2019. Users are reporting the free miles showing up instantly.

MileagePlus X app