If you previously owned a legal copy, you can find your original key by logging into your Microsoft Account
or using a command prompt tool to extract it from your own registry. Microsoft Community Hub of Office or finding a compatible free alternative Microsoft Community Hub
Many sites offering "free" keys or cracks bundle their downloads with malware, spyware, or trojans Data Theft:
Using a key without a valid license agreement is illegal and can result in a loss of software support. Professional Plus is typically a volume license