clicking Customer the blue bar below

It's my pleasure to help you with your estimate, JTPumps.

In QuickBooks Online, the Customer tab's blue bars provide limited details and do not show the date of your estimate. However, you can find the date sent by checking the Status column in the All Sales tab's blue bar. Additionally, you can include the Last Delivered column for easier access to this information.

Here's how:

1. At the left navigation panel, select Sales.
2. Click All sales, then select the blue bar.
3. On the All sales page, click the Gear icon.
4. Tick the Status and Last delivered.

Feel free to check these articles to help you enhance your business communication by personalizing your sales forms. Also, how to convert an estimate into an invoice using browsers in QuickBooks Online: 

• Customise invoices, estimates, and sales receipts in QuickBooks Online.
• Convert an estimate into an invoice in QuickBooks Online.

If you have other concerns related to QuickBooks Online, please don't hesitate to post them here in the Community space.