Something like this may work for you:
NSString *htmlPath = [[NSBundle mainBundle] pathForResource:@"yourHtml" ofType:@"html"];
NSError *error = nil;
NSString *inputHtml = [[NSString alloc] initWithContentsOfFile:htmlPath encoding:NSUTF8StringEncoding error:&error];
NSString *nameParsedHtml = [inputHtml stringByReplacingOccurrencesOfString:@"Name:" withString:[NSString stringWithFormat:@"Name: %@", self.nameField.text]];
NSString *emailParsedHtml = [nameParsedHtml stringByReplacingOccurrencesOfString:@"Email:" withString:[NSString stringWithFormat:@"Email: %@", self.emailField.text]];
NSString *outputHtml = [emailParsedHtml stringByReplacingOccurrencesOfString:@"Phone:" withString:[NSString stringWithFormat:@"Phone: %@", self.phoneField.text]];
NSLog(@"Output html string is: %@", outputHtml);