A Disaster Recovery Plan (DRP) is a business plan that describes how work can be resumed quickly and effectively after a disaster. Disaster recovery planning is just part of business continuity planning and applied to aspects of an organization that rely on an IT infrastructure to function.
The overall idea is to develop a plan that will allow the Information Technology (IT) department to recover enough data and system functionality to allow a business or organization to operate - even possibly at a minimal level.
The creation of a DRP begins with a DRP proposal to achieve upper level management support. Then a Business impact Analysis (BIA) is needed to determine which business functions are the most critical and the requirements to get the IT components of those functions operational again after a disaster, either on-site or off-site.
Source: https://www.techopedia.com/definition/1074/disaster-recovery-plan-drp