Automatically share activities on Facebook:
There are two features available to share Strava activities on Facebook. For an individual activity of your choosing, select the share icon from your activity feed or the activity details page after finishing, saving and syncing the activity to Strava. For Strava to automatically share all new activities on Facebook, the automatic share feature must be enabled from the save activity screen on either the Android mobile app or the website.
On the Android mobile app, the automatic share option appears on the screen just after finishing the recording and before saving the activity. On the Strava website, the automatic share option appears before saving manually uploaded activities by file. The automatic share option is not available on the iOS mobile app.
To enable and disable automatic Facebook sharing:
If the "f" icon or "Share to Facebook" toggle is enabled before saving an activity, then the activity will be automatically shared to Facebook when saved. This enables automatic Facebook sharing for all new activities until it is disabled. To turn off the automatic Facebook sharing, disable the Facebook share icon or toggle on the activity save screen on your next upload. If you're an iOS user, you can control this setting from the Strava website.