When one has the internet access on his mobile phone (such as via the iPhone data plan or Wi-Fi access), he could possibly also make his Mac computer (or a Windows PC) access the internet service using his existing phone’s data plan or Wi-Fi service; this configuration is known as “tethering”.
I find the following quoted “How-To Geek” article “How to Use Your iPhone’s Hotspot (or a USB Cable) for Tethering” by Chris Hoffman informative and quote some information in the article below as a reference. The article’s original source is on this web page http://www.howtogeek.com/213203/how-to-use-your-iphone’s-hotspot-or-a-usb-cable-for-tethering/
What You Need to Know About Tethering
. The hotspot feature on your iPhone allows you to connect any device to the Internet via your iPhone’s cellular data connection. You can use an USB cable to tether your iPhone to a Mac or Windows PC, too.
. This is also known as “tethering” a device such as your laptop or tablet to your phone, sharing the mobile data connection with it. Your iPhone creates a local Wi-Fi network your other devices can connect to.
. If your cellular carrier doesn’t include the feature in your cellular data plan, you may not see the Personal Hotspot option at all on your iPhone’s settings screen. You may have to pay extra to gain access to it.
. Even if you have unlimited data, there’s a good chance you have a limited amount of tethering data — or, at least, high-speed tethering data. Your carrier may charge you extra if you need more tethering data. Check your cellular plan for more details about your plan’s hotspot, or tethering, capabilities.
. Wi-Fi tethering will also drain your phone’s battery more quickly. If possible, connect your iPhone to a power source — or plug it into your laptop via USB cable — while tethering. Be sure to disable the hotspot when you’re not using it, too.
Create a Hotspot to Tether Any Device With Wi-Fi
To get started, open your iPhone’s Settings screen and tap the Personal Hotspot option between Cellular and Carrier near the top of the screen. If you don’t see the option, contact your carrier — it’s possible you have to pay them extra before you can see and use it.
Enable the Personal Hotspot feature and your iPhone’s top bar will turn blue, indicating that the personal hotspot is running in the background and draining your battery.
Your iPhone will now appear as a nearby wireless network. On any device with a Wi-Fi connection, open the list of networks and choose your device in the list — it’ll be named something like “[Name]’s iPhone.” Select it in the list and you’ll be asked for a passphrase. Enter the passphrase displayed on the Personal Hotspot screen on your iPhone. Your device will connect.
When you’re done, pick up your iPhone and disable the Personal Hotspot feature to save battery life. This is easy — your iPhone’s top bar will be blue as long as the Personal Hotspot feature is enabled. Tap it and you’ll be taken directly to the Personal Hotspot screen, where you can disable it.
Easy Wi-Fi Tethering on a Mac
Mac OS X Yosemite makes these things work well together. Click the Wi-Fi icon on the menu bar, and you’ll see your nearby iPhone appear under “Personal Hotspot.” Click it, and your Mac will automatically connect to the iPhone, enabling the Wi-Fi hotspot feature and allowing you to connect directly to the Internet.
This is convenient because it allows you to quickly connect to your iPhone from your Mac without leaving the personal hotspot feature enabled all the time. You can do this entirely from your Mac without picking up your iPhone and tapping anything. It’s only enabled when you connect to it. This saves battery life.
USB Tethering on a Mac
You can also connect your iPhone to your computer via a USB cable — not a bad idea, as the iPhone can draw power from your Mac and its battery won’t be run down by the tethering.
Go into your iPhone’s Setting screen, tap Hotspot, and Personal Hotspot near the top of the list, and enable Personal Hotspot. You can then click the WI-Fi icon on the menu bar and select Open Network Preferences. You’ll see that your Mac is tethered to the iPhone using the “iPhone USB” connection. If you don’t see it in the list, click the “+” button and add the iPhone USB network interface.
USB Tethering on Windows
USB tethering can al;so function with a Windows PC. You’ll need the latest version of iTunes installed on your Windows PC to do this, as it includes the appropriate drivers. Enable Personal Hotspot on your iPhone and then connect it ot the Windows PC using a USB cable. Your Windows PC will be able to use the iPhone as a network connection, just as a Mac could.
This should automatically configure itself if you plug your iPhone in with Personal Hotspot enabled. You’ll see the network connection appear as an “Apple Mobile Device Ethernet” connection.
iPhones also support Bluetooth tethering. Pair your iPhone with a computer or other device over Bluetooth to share the Internet connection using Bluetooth. Wi-Fi tethering will be easier to set up and faster. However, Bluetooth tethering could potentially drain your iPhone’s battery more slowly, saving some battery life.