BLE stands for Bluetooth Low Energy. This technology, like NFC (Near Field Communication), serves to establish communication between two compatible devices located within a short distance of each other (maximum 10 cm).
For the vast majority of iPhones, Seamless validation is done using NFC. This concerns iPhone 7 or higher, with an iOS version 13 or higher.
For older iPhones that do not meet these criteria, BLE technology is used for Seamless validation.
For more information on NFC technology, click on: "What is the NFC function?".
To find out how to activate the NFC function, click on: "How can I activate the NFC function on my mobile?".