Endpoint Detection and Response (EDR) is an endpoint security solution or software that continuously monitors end-user devices (Laptops, desktop, tablets, etc.) to detect and respond to cyber threats such ransomware and malware. 

Endpoint Detection and Response can sometimes be referred to as endpoint detection and threat response (EDTR). 

Due to endpoint detection and response technical nature its normally managed by an IT Service provider or Managed Service Provider (MSPs)