Recording with the Strava Mobile App
The following activity types can be recorded with the Strava mobile app: CrossFit, elliptical, stair stepper, weight training, yoga, and workout. During the recording, you'll be able to see the activity start time, elapsed time, and your heart rate if you've paired a heart rate monitor.
In the mobile app, it is not currently possible to record indoor runs or rides or to measure distance using a pedometer or other sensors. However, you can record indoor runs with the Strava Apple Watch App using your watch's pedometer to measure distance.
Recording with a Third Party App or Device
Indoor activities can be recorded with any Strava-compatible GPS device, or with a device that doesn't use GPS, as long as the data is compatible with the Strava uploader (or can be synced from another app to Strava). If you record indoors, especially with sensors for speed, cadence, or power, you should disable GPS on your device while recording. This will help with correcting the analysis of your data, such as distance and speed.
The Indoor Activity Page
The indoor activity page will not show a map. An exception to this is if you are recording and uploading virtual GPS data. Instead, the performance graph is highlighted to show your heart rate, speed, cadence, or power data, if available. If you don't have any accessory data, then there may not be a performance graph, but you will still get credit for your elapsed time.