I'm not able to set constraints for an activity indicator below a tableview but not part of the table.
I tried to add constraints to the activity indicator but unable to do it.
Even when I typed number, Add Constraints button was unable to click.
You don't want a container constraint. Your progress indicator isn't contained by your table view - they are siblings.
Tap the other button that looks like this:
And add a "spacing to nearest neighbor" constraint.