You can add a new client by registering the client in the Register New section under the Organisation on the Tax Practitioner eFiling profile.
- Login to eFiling
- Select Organisations
- Select Register new
- Complete all required information
- Add tax types
For a step by step process, refer to the following link: https://www.sars.gov.za/tax-practitioners/adding-clients-to-a-tax-practitioners-efiling-profile/