Thank you for posting here in the Community. I'd be glad to assist you with any question you may have about custom templates.
If you're referring to a column like product/service description, please make sure to enable them by putting a checkmark through the Content tab. For your visual reference, I'm adding the screenshot I recommend on this:
I've also checked here, and there are no reported issues from other users related to what's going on with your custom template. If the field is still missing, you can try recreating the custom estimate again to determine if the problem is template related.
For future reference, I'm adding the article I recommend on this:
How to create an invoice.
Please keep in touch with me here should you need any further assistance with populating the field from the custom template. The Community always has your back.
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