You can try this out.
MFMailComposeViewController *mcvc = [[MFMailComposeViewController alloc] init];
mcvc.mailComposeDelegate = self;
NSString *toAddress = //recepient_name_here;
[mcvc setToRecipients:[NSArray arrayWithObjects:toAddress,nil]];
[mcvc setSubject:subject];
[mcvc setMessageBody:emailBody isHTML:NO];
[mcvc addAttachmentData:ifAny mimeType:@"application/pdf" fileName:fileName];