CKEditor Cloud Services is hosted on AWS. Servers and infrastructure components are hosted in the US East (Northern Virginia) region and the EU (Frankfurt) region. To host your Cloud Services applications, you can choose either. Multi-region support (available with the Custom plan) lets you create and use environments in multiple regions (either EU or US) as needed. Matching your users' location will help offer improved performance of the editor inside their application, thanks to it being served from the cloud region that’s closer to the end user.
The selected region also affects data residency. The Frankfurt EU region keeps data in the EU, hence it helps your app stay GDPR-compliant. This is especially important from a business point of view, as the European region is highly regulated when it comes to personal data.
Refer to the documentation to read more.