QB Issue Resolution:

Set up an item for coupons in the items list. Then enter it on your estimate. Just make it either a negative quantity or negative amount.

Resolution for Issue 'HOw do I add coupons to an estimate?' available: Yes (Solved).
Source: Intuit Community forum.

HOw do I add coupons to an estimate?: this issue or error code is a known issue in Quickbooks Online (QBO) and/or Quickbooks. Support for this issue is available either by self-service or paid support options. Experts are available to resolve your Quickbooks issue to ensure minimal downtime and continue running your business. First try to resolve the issue yourself by looking for a resolution described below. If it is a complex issue or you are unable to solve the issue, you may contact us by clicking here or by using other support options.

Support for add coupons
Quickbooks Repair Pro will resolve it efficiently and affordably. Guaranteed resolution of your issue, or you pay nothing!

Error Recovery for add coupons [Canada]
E-Tech is the #1 Quickbooks data migration and Conversion service provider.

Get 50% off Quickbooks Online

Click Here for 50% off!

Additional Support Options: