how you could make a text appear by hovering over a picturebox [closed]

You do not have to do it in the MouseHover event. You can assign a ToolTip object to the PictureBox control at any time.

For example, you could do it in the form's own constructor. Always after the call to InitializeComponent to make sure that the PictureBox has been created:

public Form1()
{
    InitializeComponent();
    var tt=new ToolTip();
    tt.SetToolTip(pictureBox1, "Texto a mostrar");
}