Not common any more- but remember some employers still offer a defined benefit (DB) plan, or as it is commonly called a pension plan.  It's completely separate from your 401k or 403b plan..  Generally you have two choices on receiving these retirement funds.

Many defined-benefit pension plans allow employees to choose to receive all the retirement money they’ve earned over the years in a single lump-sum payout when they call it quits, or you may be able to select h income at  a certain age....it's an annuity payout over your life expectancy or a payout over your life and your survivors lifespan (joint tenant with right of survivorship).

Most often, retiree's take the lump sum and rollover to their own IRA...very common to control those funds and set up income withdrawals when they need the money.  Consult with you financial planner if you do have a separate pension plan.