These are the steps on how to add user in approval workflow in accounting: 

1. From the top level, go to Company > Setup > Approvals - Approval Policy Manager

2. Locate the policy and click Edit

3. Select the appropriate Status

4. In the Approval routing and limits section, click the Plus or Trash can icons to add or remove roles or users to the policy.

5. Under Role/User, select the needed role or user for this policy

6. Make any other changes needed in the fields shown per the Policy type selected when the policy was created

7. Click Save