Alex

You are right. The “Licenses” tab is available only in Professional version. You can upgrade to Professional version from the main menu "Help (?) - Upgrade". Such upgrade includes a renewal for one year.

If the key shows only five last characters, it means that MAK (Multiple Activation Key) or KMS (Key Management Service) is used and it is not possible to retrieve the full key automatically in any way. The full key is not stored in the registry as usual. Even the VAMT tool from Microsoft (Volume Activation Management Tool) and ospp.vbs script (cscript ospp.vbs /dstatus) in the Office installation folder can show only five last characters of the key.