My phone is entirely new and I want it to connect to the internet using mobile data. It is not showing the network type icon, so how can I fix it?

You need to pay for an internet plan - either 4G, 5G, or any other based on your phone's capacity. To learn more, you can call the sim card/service provider's customer care number. They will let you know whether you need to recharge with a 4G plan for data, and whether there is data or balance available to be used etc. Or, you can search online for the data plans and ask the retailer to activate a plan. There is a number that you can dial to get a set of instructions. Each service provider has their own number, find yours to get started.