WordPress' built-in editor has an HTML mode that lets you override the background color of a post by changing its CSS (Cascading Style Sheet) background-color attribute to the color of your choice.

In Google Docs, you can add watermark, picture and solid color background to your page. Learn how to insert Background Images in Google Docs.

The button will now have a red background color. In conclusion, you can easily change the color of buttons in HTML by using inline, internal, or external CSS. Whichever method you choose is a matter ...

Learn how to set the background color for selected text (instead of the entire document) in TextEdit ...