From www.IRS.gov: IRS Summertime Tax Tip
You may need copies of your filed tax returns for many reasons. For example, they can help you prepare future tax returns. You’ll need them if you have to amend a prior year tax return. You often need them when you apply for a loan to buy a home or to start a business. You may need them if you apply for student aid.
If you can’t find your copies, the IRS can give you a transcript of the information you need, or a copy of …