SQL Server has many features that you can put in place to implement a HA/DR solution that will fit your needs. These features include the following:
- Always On Failover Cluster
- Always On Availability Groups
- Database mirroring
- Log shipping
- Replication
In many cases, you will combine more of the features together, as your high availability and disaster recovery needs will overlap. HA/DR does not have to be limited to just one single feature. In complex scenarios, you'll plan for a primary high availability solution and secondary high availability solution that will work as your disaster recovery solution at the same time.