See this page (Apple) for the latest guide on setting up a hotspot in iOS:
A Personal Hotspot lets you share the mobile data connection of your iPhone or iPad (Wi-Fi + Cellular) when you don’t have access to a Wi-Fi network.
If you can’t see the option for Personal Hotspot, contact your network provider to make sure you can use Personal Hotspot with your plan.
You can connect to a Personal Hotspot using Wi-Fi, Bluetooth or USB. And with iOS 13 or later, devices that are connected to a Personal Hotspot will stay connected, even if the screen is locked, so those devices will still receive notifications and messages.
Here are some tips for using each method.
When you connect a device to your Personal Hotspot, the status bar turns blue and shows how many devices have joined. The number of devices that can join your Personal Hotspot at one time depends on your network provider and iPhone model. If other devices have joined your Personal Hotspot using Wi-Fi, you can only use mobile data to connect to the Internet from the host device.
Use these steps to connect:
On the device you want to connect to, go to Settings > Mobile Data > Personal Hotspot or Settings > Personal Hotspot and make sure it’s on. Then verify the Wi-Fi password and name of the phone. Stay on this screen until you’ve connected your other device to the Wi-Fi network.
On the device you want to connect, go to Settings > Wi-Fi and look for your iPhone or iPad in the list. Then tap the Wi-Fi network to join. If asked, enter the password for your Personal Hotspot.
To make sure that your iPhone or iPad is discoverable, go to Settings > Bluetooth and stay on that screen. Then, on your Mac or PC, follow the manufacturer directions to set up a Bluetooth network connection. Learn more about using Personal Hotspot with Bluetooth.
Personal Hotspot supports Bluetooth connections with Mac, PC and other third-party devices. To connect another iOS device, use Wi-Fi.