The geolocation factor allows the author to constrain the location and range of permitted access, both as an "inside" or "outside" of parameter. By tapping geolocation, simply pinch and zoom the map to set the visible area to establish the centerpoint and radius of access. Alternatively, you can type in an address or zip code as a starting point to define your geo fence. Then, toggle the slider to state whether the access is permitted only within the range, or only permitted outside of the range.
Then tap save to apply that geofence to your share, and save the overall share settings to copy link into the clipboard to share.
When editing, tap the factor to adjust the geofence from previous setting. Long-press the factor icon to clear/reset it.