Answer
Oracle Active Data Guard is the standard Oracle technology for this: it maintains one or more standby databases (up to a large number of directly connected replicas) that stay synchronized with the primary database by continuously transmitting and applying the primary's redo (change) data over Oracle Net Services, with no restriction on the standby's physical location as long as network connectivity exists. A standby is initially created from a backup of the primary without requiring Production downtime, and once configured, a standby can also be used for reporting/read workloads or as an emergency failover target. Because getting this right (and knowing how to recover if something goes wrong) is genuinely specialized DBA work, it's worth setting this up with an experienced Oracle DBA rather than as a first-time self-service configuration.