The FAFSA is the Free Application for Federal Student Aid. The FAFSA is separate from the YOUniversal application, but you may be required to fill it out in order to be considered eligible for some scholarships that you will apply for through YOUniversal.
You can fill out the FAFSA at https://fafsa.ed.gov.
The website listed above is the official FAFSA website. The application is free, so be wary of sites asking you to pay for this or any other scholarship application.
You may fill out the FAFSA at any time in the application process. You may wish to wait until you have filed your taxes in order to be able to take advantage of the IRS Data Retrieval Tool. You do not need to fill out the FAFSA before you fill out the YOUniversal application.
Once you complete your FAFSA, the Department of Higher Education will receive it automatically within two to three weeks. You will be able to see that it has been received by logging into your YOUniversal account.
The following links may help in completing the FAFSA or answering any questions you may have.