https://stackoverflow.com/questions/54725674/how-do-i-create-this-following-ui-in-swift

CurvedIndentedView.swift

@IBDesignable
class CurveIndentedView: UIView {

    @IBInspectable
    var radius: CGFloat = 50 { didSet { updatePath() } }
    
    private var shapeLayer: CAShapeLayer = {
        let shapeLayer = CAShapeLayer()
        shapeLayer.fillColor = UIColor.red.cgColor
        return shapeLayer
    }()
    
    override init(frame: CGRect) {
        super.init(frame: frame)
        configure()
    }
    
    required init?(coder aDecoder: NSCoder) {
        super.init(coder: aDecoder)
        configure()
    }
    
    override func layoutSubviews() {
        super.layoutSubviews()
        
        updatePath()
    }
}

private extension CurveIndentedView {
    func configure() {
        layer.addSublayer(shapeLayer)
    }
    
    func updatePath() {
        let angle: CGFloat = .pi / 6 // adjust this to whatever you want, between 0 and `.pi / 2`; /6 or /8 are close
        let controlPointOffset = radius / cos(angle)
        let endPointOffset = controlPointOffset + sin(angle) * radius
        
        let path = UIBezierPath()
        path.move(to: CGPoint(x: bounds.midX - endPointOffset, y: bounds.minY))
        path.addLine(to: CGPoint(x: bounds.minX, y: bounds.minY))
        path.addLine(to: CGPoint(x: bounds.minX, y: bounds.maxY))
        path.addLine(to: CGPoint(x: bounds.maxX, y: bounds.maxY))
        path.addLine(to: CGPoint(x: bounds.maxX, y: bounds.minY))
        path.addLine(to: CGPoint(x: bounds.midX + endPointOffset, y: bounds.minY))
        
        var endPoint = CGPoint(x: bounds.midX + cos(angle) * radius, y: bounds.minY + sin(angle) * radius)
        var controlPoint = CGPoint(x: bounds.midX + controlPointOffset, y: bounds.minY)
        
        path.addQuadCurve(to: endPoint, controlPoint: controlPoint)
        path.addArc(withCenter: CGPoint(x: bounds.midX, y: bounds.minY), radius: radius, startAngle: angle, endAngle: .pi - angle, clockwise: true)
        
        endPoint = CGPoint(x: bounds.midX - endPointOffset, y: bounds.minY)
        controlPoint = CGPoint(x: bounds.midX - controlPointOffset, y: bounds.minY)
        
        path.addQuadCurve(to: endPoint, controlPoint: controlPoint)
        path.close()
        
        shapeLayer.path = path.cgPath
    }
}

That yields:

You can then marry that with a rounded corner button:

@IBDesignable
class RoundedCornerButton: UIButton {

    override func layoutSubviews() {
        super.layoutSubviews()
        layer.cornerRadius = min(bounds.width, bounds.height) / 2
        clipsToBounds = true
    }

}

If you then size and position that appropriately, that yields: