Generally any WiFi card that plugs into the PCIe slot on a desktop comes with the antennas and the Bluetooth cable that plugs into the USB 2.0 port on the motherboard. My favourite makes, due to very good support, are ASUS, TPLink, and Dlink. This page at Amazon lists a number of them. Drivers are pretty straightforward to install. Also this YouTube video should help.
Can you recommend which aftermarket wi fi / Bluetooth card would work for this computer? Also I have noticed the cards dont come with hookups and antenna and is this something I should purchase as well. The computer opens up very easily and I can see where the slot is. Is this something a beginner can do. Thank you Also are the drivers easy to install?  
OptiPlex 9020 2014 I7 32 gb ram (wi fi card)