Stroke a selection or layer with color

You can use the Stroke command to paint a colored border around a selection, path, or layer. When you create a border this way, it becomes a rasterized part of the current layer.

To create shape or layer borders that can be turned on or off like overlays and are anti-aliased to create softer-edged corners and edges, use the Stroke layer effect instead of the Stroke command. See Layer effects and styles.

Choose a foreground color.
Select the area or layer you want to stroke.
Choose Edit > Stroke.
In the Stroke dialog box, specify the width of the hard-edged border.
For Location, specify whether to place the border inside, outside, or centered over the selection or layer boundaries.
Note: If the layer contents fill the entire image, a stroke applied outside the layer will not be visible.
Specify an opacity and a blending mode. (See List of blending modes.)
If you’re working in a layer and want to stroke only areas containing pixels, select the Preserve Transparency option. (See Lock layers.)