Apple recently released the newest version of iOS 11.2, earlier than its planned release. The reason cited was a software bug, and because of this new release, Apple Pay Cash, a key feature of the update, is now accessible to users.
Apple Pay Cash allows users to send and receive money directly through iMessages – a model similar to Venmo or Square Cash. The money that people send will be on a live digital Apple Pay Cash card inside the Wallet app. Users can then spend this money wherever Apple Pay is accepted, or they can send it to other people. This feature is, however, only available to users in the United States at this time.
This new feature was supposed to be released in the initial version of iOS 11. However, it was delayed along with other un-released features likes Messages in the Cloud and AirPlay2, which are yet to be released.
The roll out of Apple Pay Cash is a slow process, so if some users have not yet received the new feature, they just have to be patient and wait for the update.