For using orchestrator you require an activated license, for purchasing that license you can refer this website https://studio.uipath.com/docs/activating-your-studio-license
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Now a license can be activated on a robot.
While you’re installing robot use parameter ‘CODE’ . for instance D:\UiPathPlatform.msi CODE=123987
Once you finish the installation find regutil
( C:\Program Files (x86)\UiPath\Studio\UiPath\regutil.exe) and then use the command
regutil.exe activate /[email protected] /code=123987
Where email is your registered email and code is the code you put above