You have to create additional products.

Resolution for 'additional products issue: 'how can i add variation on product?' available: Yes.

The additional products 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 additional products issue yourself by looking for a resolution described in the article. If it is a complex additional products issue or you are unable to solve the issue, you may contact us by clicking here or by using other additional products support options.

For more information about resolving issues related to additional products in Quickbooks/QBO or to get support for the issue 'how can i add variation on product?', click the link below: