The odds are more than good that you know the answer to the above question already, but you probably know a lot of people who are not as clear on what a PMO is. For those people, you might want to refer them to Jen A. Miller’s primer on the subject for CIO magazine. She covers the basics of PMOs, such as what they are, why they can be valuable, and how many businesses are already using them (85 percent of them, incidentally, according to PM Solutions). She also briefly breaks down the different sorts of PMOs and the degree of support that each kind provides the business.
You can check out the primer here: https://www.cio.com/article/2441862/project-management/what-is-a-project-management-office-pmo-and-do-you-need-one.html