Does it have built-in wifi?

Yes, it has built-in Wi-Fi with 802.11ac Wireless LAN.

Questions & Answers: Refurbished: Dell Optiplex 3060 Micro Form Factor Desktop, Intel Hexa-Core i5 8500T 2.1Ghz, 8GB DDR4, 256GB SSD Hard Drive, Wi-Fi, HDMI, Windows 10 Pro

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Dell Optiplex 3060 Micro Form Factor Desktop, Intel Hexa-Core i5 8500T 2.1Ghz, 8GB DDR4, 256GB SSD Hard Drive, Wi-Fi, HDMI, Windows 10 Pro