Welcome to the Community! Let's get to the bottom of this issue together so your estimates reflect a custom message.
In QuickBooks, certain custom field and message character limits may prevent content from displaying as expected on the final document. Although you can view and edit your custom message within the template settings, I recommend reducing the length of the message so it displays correctly when you download the estimate.
Additionally, confirm that you've selected the custom template when creating the estimate. To do that, follow the steps below:
- On the Estimate page, click Manage.
- Go to the Design section.
- Double-check that you selected the correct template.
I'll leave this article that details character limits for QuickBooks: Character limitations for fields in QuickBooks.
Once the custom message shows up on the estimate and you're ready to turn it into an invoice, you may use this article as your guide: Convert an estimate into an invoice in QuickBooks Online.
Come back to this post if you have other concerns about your sales forms in QuickBooks. I'll be around to help you out.