Toggle Switch

If using more than one switch, make sure you give each a different number tag.
If you need to assign them to a sender function, for instance an event where value changed, assign all to the same function (same name). Delete all the additional events being created and change parameter type to UISwitch:
For instance, the following page has 6 switches:

@IBAction func warmUpHasChanged(_ sender: UISwitch) {

        print(sender.isOn)

        if sender.isOn

        {

            switch(sender.tag)

            {

            case 1 : self.warmUpHasTimer = true

            case 2: self.upperBodyHasTimer = true

            case 3: self.coreHasTimer = true

            case 4: self.lowerBodyHasTimer = true

            case 5: self.danceHasTimer = true

            default: self.coolDownHasTimer = true

                

            }

        }

        else

        {

            switch(sender.tag)

            {

            case 1 : self.warmUpHasTimer = false

            case 2: self.upperBodyHasTimer = false

            case 3: self.coreHasTimer = false

            case 4: self.lowerBodyHasTimer = false

            case 5: self.danceHasTimer = false

            default: self.coolDownHasTimer = false

                

            }

        }

        

    }