Yes it is possible to add discounts while creating a bill.
Simply enter under the Account details section the discount account (you may create one if you don’t have one under the Chart of Accounts) and enter the discounted amount in the Amount field.
Resolution for 'Amount field issue: 'Does Quickbooks online let me apply discounts when i pay a bill?' available: Yes.
The Amount field 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 Amount field issue yourself by looking for a resolution described in the article. If it is a complex Amount field issue or you are unable to solve the issue, you may contact us by clicking here or by using other Amount field support options.
For more information about resolving issues related to Amount field in Quickbooks/QBO or to get support for the issue 'Does Quickbooks online let me apply discounts when i pay a bill?', click the link below: