Nearly all smartphones are capable of sharing their mobile data connection as a Wi-Fi hotspot. This feature is great for getting other devices like a tablet or a Chromebook online. Hotspots can work in one of two ways, with the first sharing your standard mobile data with other devices. This is nice because you don't have to worry about managing a second data pool, but it will eat into the data you need for phone usage. This is common on the cheapest data plans such as Mint Mobile's 5GB, 10GB, or 15GB plans.
The second way is with dedicated hotspot data. Most unlimited plans use this approach with unlimited data on your phone, and a smaller amount for devices connected through the hotspot. Verizon, for example, includes 60GB of high-speed hotspot data with its Unlimited Ultimate plan. Some carriers offer unlimited hotspot data with speed caps. Visible, for instance, offers unlimited hotspot data at a maximum speed of 10Mbps on its higher plan.