The authority, exactly
Open only through a SIRI-certified employer, not to any employer in Denmark. SIRI states certification requires at least 10 full-time employees on a permanent basis, salary and terms of employment corresponding to Danish standards, and the employer's attendance at a guidance meeting with SIRI, among other conditions — it is the employer that holds certified status, not you. Once your employer is certified and submits the application, SIRI states it can issue a provisional work permit the same day if you are exempt from the visa requirement or can otherwise enter Denmark legally, or decide your case in about 10 days where you need a visa to enter.