An eSIM, a digital SIM card, works just like its physical counterpart. It identifies your device virtually and connects you to a mobile network. 5G and 4G coverage is also usually available, but coverage may depend on the network providers, the country you are based in, and your device compatibility.
Furthermore, unlike physical SIM cards, eSIMs are programmable remotely via software, which allows the device to support multiple eSIM profiles.
After choosing the right country, the amount of data that you have chosen with your eSIM plan for that country will be the amount you will be getting for the entirety of the requested period, which does not reset daily.