There are a few ways to add borders to layers in Gimp. The easiest way is to use the layer border tool. To use this tool, you need to select the layer you want to border and then click on the border tool. The border will be added automatically. If you want to add a custom border, you can do this by clicking on the Edit button and then clicking on the Custom button. Then, you can enter your own text or image into the Custom field and click on OK.
