This usually applies to investment or rental properties. It's a method of deferring potential capital gains by investing the proceeds into other qualified "like-kind" properties. If this is your primary residence that you purchased without transferring proceeds from an investment property, it doesn't apply to you.
See this IRS link for further detail on like-kind exchanges https://www.irs.gov/uac/like-kind-exchanges-under-irc-code-section-1031
