Need to know daily release frequency for Defender Signatures.

tusharkotwal Thanks TK for your question.

Updates are continuously released for cloud protection, security intelligence, and more to ensure continuous protection.

You can see more information here:

Manage Microsoft Defender Antivirus updates and apply baselines | Microsoft Docs

Schedule Microsoft Defender Antivirus protection updates | Microsoft Docs

Cloud protection and Microsoft Defender Antivirus | Microsoft Docs

Let me know if that helps. Thanks!

Marc