If you move before filing your tax return, put the new address on your return. The IRS will update your records when they process your return.
If you move after filing your return, have the post office forward mail to your new address. Some post offices don't forward government checks, so you may also want to change your address with the IRS. You can use IRS Form 8822, Change of Address (form and instructions) to notify them of an address change.