You are required to file a tax return for 2018 if your taxable income was more than $12,000. If it was not, you don't have to file, but you might be entitled to a refund of any withholding.
It's your responsibility to keep copies of your important records. You should be able to get copies of your W-2s from your employers. You can also request a document transcript from the IRS that will contain the same information, that you may be able to use to fill out the FAFSA.
