APN (Access Point Name) is the name of an access point without which it is impossible to go online. It is the so-called packet data identifier, which allows people to use the mobile Internet. The principle of the technology can be described as follows: the operator receives an APN request from the subscriber and then sends the user the correct address.
Depending on the operator, the access point’s name may be different. Therefore, it is better to clarify the name and other details in person. You can send a USSD request or read the information on the mobile operator’s website. You can also learn about connecting to mobile Internet on your Xiaomi smartphone in this article.
Then, with the received data, go to the phone settings and follow this path: “SIM-cards and mobile networks” → “SIM-card settings” → “Access points (APN)” → “The desired access point” → “APN point”.
The section names may differ depending on the phone model and MIUI version.