The integration for Excel allows users to query the API to automatically generate Excel tables about topics.
The integration is an Excel TaskPane Add-in, which is structured as an HTML / CSS / Javascript web app running in an iframe.
The underlying API runs models with weights from the GPT-3 family with many speed and throughput improvements.
More info:

https://docs.microsoft.com/en-us/office/dev/add-ins/overview/learning-path-beginner
https://docs.microsoft.com/en-us/office/dev/add-ins/excel/excel-add-ins-core-concepts

Source: https://openai.com/blog/openai-api/