Damage or Heal based on the buttons you press
not so much but some tiny changes:

DRY

i just would avoid all the self.healthBarView.frame.size.width 

and make methods:


getWidth
setWidth(or updateWidth because you set the diff)


Constants

the magic numbers like 0.1 0.05 10 i would define as constants so it can changed only at one place. 7.63 i would calculate 

Naming

rename barAmount to maxAmount

create minAmount

Float/CGFloat

the Float / CGFloat is realy needed? just put them also into getWidth and updateWidth 

else if 

the else if block is not needed (same condition)

7.63

this is an value depending on your setup - it should also calculated so it not changes when you init it with different width

Resulting Code

import UIKit

class ViewController: UIViewController {


    @IBOutlet weak var armorBarView: UIView!

    @IBOutlet weak var healthBarView: UIView!

    var damageAmount : Float = 0.0
    var healAmount : Float = 0.0

    // Min/Maximum Health
    var minAmount: Float = 0.00
    var maxAmount : Float = 0.0

    // how much damage was left after this number of hits
    let minAmountHits:Float = 10

    let demageFactor: Float = 0.10
    let healFactor: Float = 0.05

    override func viewDidLoad() {
        super.viewDidLoad()

        initAmount()
    }

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
    }

    func initAmount(){
        damageAmount = getWidth() * demageFactor
        healAmount = getWidth() * healFactor
        maxAmount = getWidth()
        minAmount = maxAmount - minAmountHits * damageAmount
    }

    @IBAction func damageBar(_ sender: UIButton) {
        if getWidth() &gt; minAmount {
            updateWidth(-damageAmount)
        }
    }

    @IBAction func healBar(_ sender: Any) {
        if getWidth() &lt; maxAmount {
            updateWidth(healAmount)
        }
    }

    func getWidth() -&gt; Float {
        return Float(self.armorBarView.frame.size.width)
    }

    func updateWidth(_ amount: Float) {
        self.healthBarView.frame.size.width += CGFloat(amount)
        print(self.armorBarView.frame.size.width)
    }
}