Once a pull request has been merged to the dev branch, the connector owner can submit the connector for certification through the Connector certification tab in ISV Studio. Once certified, the Microsoft Certification team will handle merging the updates from dev to master.
Under the Home heading, select Marketplace offers card.
On the Marketplace offers | Overview page, select Microsoft 365 and Copilot program.
On the Microsoft 365 and Copilot page, select New offer > Power Platform Connector.
In the Name field in the New Power Platform Connector screen, enter a unique name for your offer.
This name is used to help you identify your offer in Partner Center. We recommend that you include the name of your connector and associated plugin.
Next, you're taken to the Product setup page. You don't need to enter information here. The Status is marked as Complete to indicate there's nothing for you to do.
This is now obsolete, and isv studio as domain are not accessible anymore as per https://learn.microsoft.com/en-us/power-platform/important-changes-coming#isv-studio-removed
New process was published here https://learn.microsoft.com/en-us/connectors/custom-connectors/submit-for-certification#submit-your-package-for-certification
Partner center is still not updated and the option described in the documentation is not available
New process: