I suggest starting with the simplest:
1 Way to distribute the Internet from a smartphone or tablet.
Almost all smartphones and tablets support 3G / 4G. The easiest way "give out" Internet using these gadgets. Here is an example article on how to set it up – How to distribute the Internet using Wi-Fi from an Android tablet / phone. The advantages of this method are obvious – for this method you do not need to purchase any additional equipment (almost everyone has a smartphone or tablet), the downside is the discharge of the battery.
2 Way to distribute the Internet using a mobile 3G / 4G Wi-Fi router.
For this method, it is enough to purchase a mobile 3G / 4G Wi-Fi router, insert a SIM card in it and use it. The advantages of this method are the autonomy of the device, we can take it with us and use it anywhere, cons – its purchase and dependence on the battery level.
3 Way. Distribute 3G / 4G Internet from a laptop.
This method requires a laptop and a 3G / 4G modem. Everything is quite simple, the modem connects to the laptop and distributes the Internet via Wi-Fi. The advantage of this method is relative cheapness, of course, if you already have a laptop and a modem, minus the laptop should be constantly on. Here is an article about distributing the Internet using a laptop.
4 Method. Distribute the Internet using a bunch of Wi-Fi router + 3G / 4G modem.
For this method, you must have a router with support for 3G / 4G modem and the modem itself. Connect the modem to the router, configure the Internet in the router and that’s it. You get not only wireless Wi-Fi Internet, but also 4 LAN ports for connecting additional equipment that is not equipped with a Wi-Fi module (computer, TV). An example of how to organize this on routers / 3240. Pros- such a system can work around the clock 24/7, cons-purchase of additional equipment-router.
5 Method. Distribute the Internet using a router with a built-in 3G / 4G module.
Another way, it follows from 4 ways, if you want to use only 3G / 4G Internet, then it will be more convenient for you to buy a router with a combined modem, i.e. a single device into which a SIM card is inserted and this device distributes Internet via Wi-Fi, has LAN ports for connecting a computer, TV or NAS. Pros – one combined device, cons – the price of this device.
In this article, I described all the methods for distributing the Internet 3G \ 4G known to me. If you know more ways, you can write in the comments.