What I already found is
[[UIApplication sharedApplication] openURL:[NSURL URLWithString:@\"mailto:\"]];
But I just want to open the Mail ap
NSString *recipients = @"mailto:first@example.com?cc=second@example.com,third@example.com&subject=Hello from California!";
NSString *body = @"&body=It is raining in sunny California!";
NSString *email = [NSString stringWithFormat:@"%@%@", recipients, body];
email = [email stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding];
[[UIApplication sharedApplication] openURL:[NSURL URLWithString:email]];