Connect your Mac to the Internet
These days it’s easy to connect to the Internet from your Mac, whether you’re at home, at work or on the go. Two common ways to get online are by using a Wi-Fi (wireless) or Ethernet (wired) connection. If neither is available, you may be able to use an Instant Hotspot.
Use Wi-Fi
When a Wi-Fi network is available to your Mac, the Wi-Fi icon 
is shown in the menu bar at the top of the screen. Click the icon, then choose a network to join. If you see a lock icon 
next to the network name, the network is protected by a password — you’ll need to enter the password before you can use that Wi-Fi network. How to connect using Wi-Fi.
Use Ethernet
You can use Ethernet either through an Ethernet network or through a DSL or cable modem. If Ethernet is available, connect an Ethernet cable to the Ethernet port on your Mac, identified by this symbol 
. If your Mac doesn’t include a built-in Ethernet port, you can use an adapter to connect the Ethernet cable to the USB or Thunderbolt port on your computer. How to connect using Ethernet.
Use Instant Hotspot
If you don’t have access to a Wi-Fi or Ethernet connection, you may be able to use your Mac and Instant Hotspot to connect to the internet using the personal hotspot on your iPhone or iPad. How to connect using your iPhone or iPad.
At home, at work or on the go
When you’re at home: Your ISP may offer a Wi-Fi or Ethernet Internet connection. Check with your ISP if you’re not sure which type of access you have.
When you’re at work: You may have a Wi-Fi or Ethernet network connection available. Check with your company’s IT department or network administrator for details about how to connect to your work network, and usage policies.
When you’re on the go: You can use Wi-Fi hotspots (wireless networks that are open to the public) or Instant Hotspot on your Mac (if your Mac and your phone carrier support it). Keep in mind that some Wi-Fi hotspots require that you enter a password, agree to terms of service, or pay a fee to use it.