Yes you can,
- Click GST in the Left hand menu
- Click Edit GST and then Edit rates
- Click Add tax rate
From there fill in the information for the tax code.
Resolution for 'additional tax issue: 'Can you add additional tax codes?' available: Yes.
The additional tax 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 tax issue yourself by looking for a resolution described in the article. If it is a complex additional tax issue or you are unable to solve the issue, you may contact us by clicking here or by using other additional tax support options.
For more information about resolving issues related to additional tax in Quickbooks/QBO or to get support for the issue 'Can you add additional tax codes?', click the link below: