AI used through a cloud service (ChatGPT, Copilot, Azure AI, Gemini) falls under Scope 3 Category 1, because you are buying a service, not the data centre's electricity. The only exception is self-hosted AI on your own servers, which goes under Scope 2. Separately, AI built into a product you sell falls under downstream Scope 3 (Category 11, use of sold products).
Read the source article: AI Scope 3 emissions: how to count AI in your carbon footprint