Creates Amazon QuickSight customizations for the current Amazon Web Services Region. Currently, you can add a custom default theme by using the CreateAccountCustomization or UpdateAccountCustomization API operation. To further customize Amazon QuickSight by removing Amazon QuickSight sample assets and videos for all new users, see Customizing Amazon QuickSight in the Amazon QuickSight User Guide.

You can create customizations for your Amazon Web Services account or, if you specify a namespace, for a QuickSight namespace instead. Customizations that apply to a namespace always override customizations that apply to an Amazon Web Services account. To find out which customizations apply, use the DescribeAccountCustomization API operation.

Before you use the CreateAccountCustomization API operation to add a theme as the namespace default, make sure that you first share the theme with the namespace. If you don't share it with the namespace, the theme isn't visible to your users even if you make it the default theme. To check if the theme is shared, view the current permissions by using the [DescribeThemePermissions](https://docs.aws.amazon.com/quicksight/latest/APIReference/API_DescribeThemePermissions.html) API operation. To share the theme, grant permissions by using the [UpdateThemePermissions](https://docs.aws.amazon.com/quicksight/latest/APIReference/API_UpdateThemePermissions.html) API operation.