Generally, essays for college admission follow a simple format that includes an opening paragraph, a lengthier body section, and a closing paragraph. You don't need to include a title, which will only take up extra space. Keep in mind that the exact format can vary from one college application to the next. Read the instructions and prompt for more guidance.
Most online applications will include a text box for your essay. If you're attaching it as a document, however, be sure to use a standard, 12-point font and use 1.5-spaced or double-spaced lines, unless the application specifies different font and spacing.