How to Fill a Selection with a Solid Color in Photoshop
When you just want to add a solid color while working in Photoshop CS6, you use either the foreground or the background color. (These colors appear at the bottom of the Tools panel.) The following steps show you the basics of filling a selection with either the foreground or the background color (you have plenty of other Fill options as well.):
Create your selection on a layer.
Select a fill color as the foreground or background color.
Choose Window→Color. In the Color panel, use the color sliders to mix your desired color.
The Fill dialog box appears. In this dialog box, under Contents, you can select whether to fill with the foreground or the background color. You also can select Color (which launches the Color Picker), Black, 50% Gray, White, History, Pattern, or the Content-Aware option.
The color that you choose fills the selection.
You can select a blending mode, the fill opacity, and choose whether to fill the entire selection or only the portions of the selection that contain pixels (the nontransparent areas). It’s recommended to not adjust your Blending Mode or Opacity settings in the Fill dialog box; instead create a new layer for your fill and adjust those settings in the Layers panel, where you have more flexibility.