Can I share internet from a SIM card in Vietnam?

Yes, you can. If you buy a local SIM card in Vietnam, you can easily set up a WiFi hotspot and use the internet on multiple devices. For more details on everything you need to know about buying a SIM card in Vietnam, see here - https://nashaplaneta.net/asia/vietnam/internet-i-mobilnaya-svyaz-vo-vietname

How much does a visa to Vietnam cost?
Where to go in Vietnam for the first time?
Where is best to buy tours to Vietnam?
Follow the link, all these questions are discussed in the chat - https://t.me/vietnam_travel_chat