Dear Ayca,
As a System Integrator (SI), you are expected to collaborate with a taxpayer to test your implementation. In this setup, the taxpayer will provide you with their Business ID, Service ID, and other required parameters for integration and validation.
Alternatively, if you are also registered as a taxpayer on the platform, you may enable your own business for e-Invoicing and use your credentials to perform test transactions and validate your integration flow.
