The final notice and the hearing right
Before most levies, the IRS must send a notice of intent to levy that explains your right to a Collection Due Process hearing. A request made within a short deadline generally keeps the IRS from levying for the periods covered while the hearing is pending, and the decision can be reviewed by the Tax Court. A late request can still lead to an equivalent hearing, but without that protection or court review. There are narrow situations in which the IRS can levy first and offer the hearing afterward, such as some levies on state tax refunds. Reading the exact title and date of the letter you received tells us which situation applies.
What the hearing can be used for
The hearing is held with the IRS Independent Office of Appeals, which is separate from the collection function that sent the notice. It is a place to propose a collection alternative such as an installment agreement or an offer in compromise, and to ask that a levy not go forward. You may also be able to dispute the underlying tax if you never had an earlier chance to do so. Appeals generally expects current financial information and filed returns, so arriving without them weakens the request. Collection Appeals is a different program that can be used in some situations where a hearing is no longer available.
When a levy has already happened
If wages or other property are already being taken, the IRS can release a levy in certain circumstances, including when it is creating economic hardship, although the debt remains. Agreeing to a payment plan often leads to release, and an offer or a hardship status may as well. Gather the levy notice, the final notice that preceded it, your most recent returns, and documentation of income and household expenses. In a first meeting we confirm which periods are involved, check whether any hearing deadline is still running, and decide what to present to the IRS first.