BackColor and ForeColor properties are used to set background and foreground color of a Button respectively. If you click on these properties in Properties window, the Color Dialog pops up.
Alternatively, you can set background and foreground colors at run-time.
The following code snippet sets BackColor and ForeColor properties.
private void Form1_Load(object sender, EventArgs e)
button1.BackColor = Color.Red;
button1.ForeColor = Color.Blue;