A federal tax levy is when the IRS legally takes over a taxpayer's real estate, vehicles, wages, bank accounts, or any other property in order to cover the tax debt.
A taxpayer can get then levy released by appealing to the IRS. The IRS may release the levy if (among others):
the taxpayer pays the debt
the IRS determines that the levy puts the taxpayer in immediate economic hardship- e.g. they determine that due to the levy, the taxpayer cannot meet his/her basic living needs
the taxpayer enters into an installment agreement where a levy is not allowed to continue
A tax levy is the most severe collection tool of the IRS. The best way to avoid a tax levy: Don't ignore the IRS and let a tax professional help deal with the problem.