How to create click event on label in xamarin forms dynamically

Try this :

var forgetPasswordLabel = new Label   // Your Forget Password Label
{
    Text = "Forgot Password?",
    FontSize = 20,
    TextColor = Color.Blue,
    HorizontalOptions = LayoutOptions.Center,
};


// Your label tap event
var forgetPassword_tap = new TapGestureRecognizer();   
forgetPassword_tap.Tapped += (s,e) =>
{
    //
    //  Do your work here.
    //
};
forgetPasswordLabel.GestureRecognizers.Add(forgetPassword_tap);

Sample :

var forgetPasswordLabel = new Label   // Your Forget Password Label
{
    Text = "Forgot Password?",
    FontSize = 20,
    TextColor = Color.Blue,
    HorizontalOptions = LayoutOptions.Center,
};

MainPage = new ContentPage
{
    BackgroundImage = "background.png",
    Content = new StackLayout
    {
        VerticalOptions = LayoutOptions.CenterAndExpand,
        HorizontalOptions = LayoutOptions.CenterAndExpand,
        Spacing = 50,
        Children = {

            new Label {
                //HorizontalTextAlignment = TextAlignment.Center,
                Text = "Welcome, Please Sign in!",
                FontSize=50,
                TextColor=Color.Gray,
            },


            new Entry
            {
                Placeholder="Username",
                VerticalOptions = LayoutOptions.Center,
                Keyboard = Keyboard.Text,
                HorizontalOptions = LayoutOptions.Center,
                WidthRequest = 350,
                HeightRequest = 50,
                FontSize=20,
                TextColor=Color.Gray,
                PlaceholderColor=Color.Gray,
            },

            new Entry
            {
                Placeholder="Password",
                VerticalOptions = LayoutOptions.Center,

                Keyboard = Keyboard.Text,
                HorizontalOptions = LayoutOptions.Center,
                WidthRequest = 350,
                HeightRequest = 50,
                FontSize=25,
                TextColor=Color.Gray,
                IsPassword=true,
                PlaceholderColor =Color.Gray,
            },
            new Button
            {
                Text="Login",
                FontSize=Device.GetNamedSize(NamedSize.Large,typeof(Button)),
                HorizontalOptions=LayoutOptions.Center,
                VerticalOptions=LayoutOptions.Fill,
                WidthRequest=350,
                TextColor=Color.Silver,
                BackgroundColor=Color.Red,
                BorderColor=Color.Red,
            },
            forgetPasswordLabel
        }
    }
};

var forgetPassword_tap = new TapGestureRecognizer();
forgetPassword_tap.Tapped += (s,e) =>
{
    //
    //  Do your work here.
    //
};
forgetPasswordLabel.GestureRecognizers.Add(forgetPassword_tap);

For people who prefer to use XAML and who like to bind Command directly to the ViewModel, you can use this:

<Label HorizontalOptions="Center"
       TextColor="Blue"
       FontSize="20"
       Text="Forgot Password?">
    <Label.GestureRecognizers>
        <TapGestureRecognizer Command="{Binding ForgotPasswordCommand}" />
    </Label.GestureRecognizers>
</Label>

And then in your ViewModel, you'll just assign the command to your function:

public ICommand ForgotPasswordCommand => new Command(OnForgotPassword);

And then define the function with all the work get done:

private async void OnForgotPassword()
{ ... }

PS: You will need to declare that you are using System.Windows.Input;