The Bucket Fill tool in GIMP fills a selection with the current foreground color. It can also fill with the background color by Shift+ clicking and using the Bucket tool.
• You can select the Bucket Fill tool from the image-menu through: Tools > Paint Tools > Bucket Fill or by clicking the tool icon: 
in the toolbox or by pressing the Shift + B keys.
• Choose the desired colour or pattern & fill.
