All the details for MD Covid Alert app are at the Maryland Dept. of Health covidLINK site. 

There are separate apps for Virginia and DC if you happen to live there. These are all administered by the state public health officials.

These apps all work the same way. They do not track your location. They track who has been around you at a distance of 6 feet or less for at least 15 minutes. If any of those people who you have been around report a positive test, you will be alerted and given instructions.

In iOS, you may have received an alert on your phone about it’s availability. Android requires a download through the Google Play Store. It does require iOS 13.7 or later or Android version 6 (API 23) to work.