AgoraVideoViewController.swift

@IBAction func didTapAddFriend(_ sender: Any) {
    let storyboard = UIStoryboard(name: "UserSearchViewController", bundle: nil)
    let searchVC = storyboard.instantiateInitialViewController()!

    // Use the popover presentation style for your view controller.
    searchVC.modalPresentationStyle = .popover

    // Present the view controller.
    self.present(searchVC, animated: true) {

    }
}