If you ever need a copy of old 1040 tax forms, there are a few options for you to pursue.
Transcript or Full Return?
Depending on what you need the return for, you can sometimes get away with providing only a transcript. A transcript is just a listing of all the line items from your tax return and won’t include copies of your W-2, 1099s, or other documents filed. These usually satisfy the needs of most requests, such as a bank, and are provided free of charge from the IRS via Form 4506-T: Request for Transcript of Tax Return  or by calling 1-800-829-1040 to place your order.
If you need the whole thing, there are two options.
If you used a tax preparer, such as H&R Block, you should call them first. They usually will keep copies of your tax returns on record for a few years and can provide a copy for you. They may or may not charge a fee but it’s often the quickest way you get a copy of your return.
If the preparer doesn’t have a copy or you didn’t use one, you can submit a request directly to the IRS on Form 4506: Request for Copy of Tax Return  for $39 a piece, paid with the form, and up to 60 days.