There is a Publish button in UiPath Studio which will publish the package to Orchestrator. This will only work if you have the robot and license set up. You can find out if this is set up by opening the UiPath Robot application and check if the status is “Connected with License”.
Alternatively, you can use the Publish window to create a local package. Then go to the Orchestrator page, got to Processes, click on the Packages tab at the top, and then click the icon for uploading the package you saved to Orchestrator.