Configure Internet Sharing under System Settings > General > Sharing. Use the “i” button to select a source and destination connection, then turn on Internet Sharing and connect using a second device.
Your Mac can function as a wireless hotspot, allowing you to connect your other devices to it and share its Internet connection. It’s just like tethering to your iPhone.
This is most useful if your MacBook or desktop Mac is connected to a wired network interface via Ethernet. You can connect your wireless devices to your Mac and share the wired Internet connection with them—almost as if your Mac were a wireless router.
Enable Internet Sharing and Configure Your Hotspot
The Wi-Fi hotspot option is part of your Mac’s Sharing features in macOS. You’ll find it under System Settings > General > Sharing.
(Click the Apple menu and select “System Settings” to open the System Settings window.)
You’ll see an option for “Internet Sharing” in the list. Resist the urge to turn it on just yet, as you’ll need to set everything up first.
Now it’s time to select the Internet connection you want to share with the devices. Click on the “i” information button alongside Internet Sharing to see a list of available connections and destinations. Be aware that you can’t share a Wi-Fi connection that you’re already connected to. If you want to share via Wi-Fi, you’ll need to share another type of connection instead.
For example, let’s say your Mac is connected to the Internet through an Ethernet adapter. You’d select “Ethernet Adapter” in the list at the top of the window and share that wired connection with “Wi-Fi” below. If you want to share your iPhone’s cellular internet connection via USB-to-Lightning cable, you can select “iPhone USB” at the top, then check “Wi-Fi” in the box below.
Click the “Wi-Fi Options” button at the bottom of the window to configure your Wi-Fi hotspot. Select your preferred network name and the best Wi-Fi channel. Use the “Security” box to select “WPA2/WPA3 Personal” to maximize compatibility with older devices (you can also choose WPA3-only, which is more secure).
macOS won’t let you proceed if you don’t set a password here, so it’s impossible to create a Wi-Fi hotspot that anyone can connect to without a password.
Finally, head back to System Settings > General > Sharing and enable the “Internet Sharing” toggle in the list. Authorize the change with your fingerprint or admin password, and your connection will be shared.
If You Want to Share a Wi-Fi Connection
Your Mac’s Wi-Fi interface can either be connected to a Wi-Fi network or host its own network—it can only do one of these things at a time. This means you can’t be both connected to a Wi-Fi network and share that Wi-Fi network’s connection over Wi-Fi. Yes, you may sometimes want to do this—for example, when you’re staying in a hotel or other location that only allows you to connect one device to its Wi-Fi network.
Sharing a Wi-Fi network connection by creating another Wi-Fi network will require a separate physical network interface, such as the WiFi Nation AC600 Mini 802.11ac Dongle. This allows you to connect to a network with one adapter and then share via another.
External Wi-Fi Adapter
To share your existing wireless network without an additional adapter you’ll need to choose “Wi-Fi” as the source connection and share via another method. This could be to your iPhone via a cable with the “iPhone USB” option, via a Thunderbolt cable to another Mac (using “Thunderbolt bridge”) or via good old Ethernet.
Some older Mac models can create a Bluetooth PAN (Personal Area Network), but this option is absent on newer machines like M1 and M2 Macs. These networks can take a bit longer to connect to—thanks to the Bluetooth pairing process—and can’t reach the speeds of Wi-Fi, but may be a bit lighter on your Mac’s battery life.
Troubleshooting Common Connection-Sharing Problems
If you have trouble connecting to a Wi-Fi hotspot you have created, remember that you can always head back to System Settings > General > Sharing and click on the “i” next to Internet Sharing to access the “Wi-Fi Options” menu. This allows you to reset your password, rename the hotspot, or downgrade the security protocol.
While you may prefer to always use a VPN, you should consider disabling your VPN if you are having trouble connecting. You can always try re-enabling your VPN connection once any client devices have connected.
If you’re using a cable connection to bridge the gap, try switching out your Ethernet or Lightning cable if things aren’t working as expected. Ethernet cables, in particular, can degrade as they age without showing any obvious signs, so it’s always good to have a few spares you can use for testing. If your Lightning cable is starting to fray, it’s probably time to throw it away.
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Source : https://www.howtogeek.com/214053/how-to-turn-your-mac-into-a-wi-fi-hotspot/