You can get a copy of a previously-filed return from the IRS.
When requesting your copy, you can choose either a tax return transcript, which is free, or an exact copy which costs $50 (the fee may be waived in Presidentially-declared disaster areas).
They're available for the current and past three years, and take 5-10 days to arrive in your mailbox.
Order your transcript from the IRS Get Transcript service (you can receive the transcript online or by mail), or by calling their toll-free number 1-800-908-9946 (receive the transcript by mail only).
Exact copies include your W-2s and all attachments, and are available for the current and past six years. To order, fill out Form 4506. Please allow up to 75 days for delivery.
Tip: Most lenders will accept a transcript in lieu of an exact copy, but it's best to double-check with your lender.
For more information about ordering tax returns from the IRS, see IRS Tax Topic 156.