Thanks for reaching out to the Community, Nancy1988.
When creating an estimate, if you've specified no product or service for a line item, it's PRODUCT/SERVICE column will default to Design:Services upon saving the document into your books.
Here's an image showing how it works:

I can certainly understand how an ability to save estimates without any products or services appearing on them could be useful and have submitted a suggestion about it as of today.
You can also submit your own feature requests while signed in.
Here's how:
- Use the Gear icon, then go to Feedback.
- Enter your suggestion(s) in the Have feedback? window.
- If necessary, attach a file with your Camera icon.
- Select Next.

Your feedback's definitely valuable to Intuit. It will be reviewed by our Product Development team and considered in future updates. You can stay up-to-date with the latest news about your product by reviewing Intuit's Product Updates webpage.
Please feel welcome to send a reply if there's any additional questions. Have an awesome Wednesday!