I can help you with sending a batch transaction using your customized template, @Naveeds. 

Can you tell me more about the error you've encountered when trying to customize the email template and creating a new one? That will help me resolve the error you're having. 

You can go to the Company Preferences to create an email template for your batch transactions. Once you're done, you can choose the Template you've created when sending it. 

Here's how:

1. Go to the Edit menu and select Preferences.
2. Select the Send forms menu and then the Company Preferences tab.
3. From the Delivery Method Default dropdown menu, select Email.
4. From the Email Templates dropdown menu, select a transaction type. You can create multiple templates for each transaction type transaction listed.
5. Select Add Template and create a template a name.
6. Create or recreate your template
7. Click on Save once done and then OK to save your changes.

Check this article for more information customizing email templates and using them to send messages: Create custom email templates in QuickBooks Desktop. 

If it's not using your new template, here's how to fix email template issues.

Let me know if you need more help creating and using the template you'd like when sending your batch transactions. I'm always here to assist. Have a wonderful day!