Electronic mail is a method of exchanging digital messages from an author to one or more recipients.
The problem of logistics: Much of the business world relies upon communications between people who are not physically in the same building, area or even country; setting up and attending an in-person meeting, telephone call, or conference call can be inconvenient, time-consuming, and costly. Email provides a way to exchange information between two or more people with no set-up costs and that is generally far less expensive than physical meetings or phone calls.
The problem of synchronization: With real time communication by meetings or phone calls, participants have to work on the same schedule, and each participant must spend the same amount of time in the meeting or call. Email allows asynchrony: each participant may control their schedule independently.