Do I need Wi-Fi to send and receive iPhone texts and calls on my Mac?

iOS 8 and Yosemite's Continuity feature allows you to relay both SMS texts and calls to any of your other devices running iOS 8 (8.1 for text relay) or OS X Yosemite. Despite the amount of sites out there that say you need both devices to be on the same Wi-Fi network for text message forwarding, you do not, in fact, need it. You can find instructions for setting up SMS text forwarding here.

On the other hand, making and receiving calls on your computer does require both devices to be connected to the same Wi-Fi network. See "How to Make and Take iPhone Calls on Your Mac" for further detail.