Why is my hotspot icon not switching on when I tap it?

Hi Korede, hotspot is a device feature, it depend on the type of phone you are using, if the device is an iPhone, you can use the steps below to set it up.
Below are the steps on how to set-up your iPhone as a mobile hotspot (iOS)
1. Go to Settings
2. Select Cellular
3. Tap on Cellular Data Options
4. Then on Cellular Data Network
5. Scroll down to Personal Hotspot area (username and password is web while APN is web.gprs.mtnnigeria.net then save)
6. Go back one step to cellular section
7. Toggle it on
8. You can also change password to make it easier to remember