If you have moved since you filed your return and were expecting your refund in the mail, you should know that the IRS won't forward a refund check. Instead, it will be returned to the IRS. You should contact the IRS and state tax authority (if you filed a state return) and report your new address.
Also, you can submit a Form 8822 to change your address with the IRS. They may not receive it until the refund is processed, but the new address will on file with them. Go to this link for that form How To Change Your Address With The IRS.