Using Applications & Creating Documents
You use an application by opening, or launching, it. It loads into the computer's memory, or RAM. Its menu bar replaces the Finder's menu bar and offers commands that can be used only with that application. It may also display a document window and tools specific to that program.
Most applications create documents—files written in a format understood by the application. When you save documents, they remain on disk so you can open, edit, print, or just view them at a later date.
For example, you may use Microsoft Word to write a letter. When you save the letter, it becomes a Word document file that includes all the text and formatting you put into the letter, written in a format that Microsoft Word can understand. ...