Hi,
Please refer to the following article it has complete information how to get user details.
How to: Get user identity and properties in SharePoint 2013
Using PeopleManager, we can get the emailID.
PeopleManager peopleManager = new PeopleManager(clientContext);
PersonProperties personDetails = peopleManager.GetMyProperties();
clientContext.Load(personDetails, personsD => personsD.AccountName, personsD => personsD.Email, personsD => personsD.DisplayName);
clientContext.ExecuteQuery();
Please mark it answered, if your problem resolved.