A hotspot is a feature that allows a phone to share its cellular data connection with other devices via Wi-Fi, Bluetooth, or USB. This can be useful when traveling on a train, where Wi-Fi networks may not be available or reliable. A hotspot can provide internet access to a laptop or other devices that need to connect to the web.

Bluetooth is a wireless technology that allows devices to communicate over short distances, usually within 10 meters. It can be used to pair devices such as headphones, speakers, keyboards, mice, etc. However, it cannot be used to share internet access from a phone to a laptop.

Near-field communication (NFC) is a wireless technology that allows devices to exchange data by touching or bringing them close together, usually within 4 cm. It can be used for applications such as contactless payments, smart cards, digital tickets, etc. However, it cannot be used to share internet access from a phone to a laptop.

Roaming is a feature that allows a phone to use another carrier’s network when the home network is not available. This can be useful when traveling abroad, where the home network may not have coverage or agreements with local operators. However, roaming can incur additional charges and may not provide the same speed or quality of service as the home network. Roaming does not affect the ability of the phone to share internet access with other devices via hotspot.