The final step is to "Save As" in the file format for your intended project. If I wanted to save a photograph for use in a Web page, I'd probably save as a JPEG. Many factors play into a decision as to which file format to use, but many folks don't want to think about it that much. If this describes you, then take a look at "Which Graphic Format Should I Use?"
Choose one of the following links for the software you'll be using.