By default, the maximum number of fields that can be added within the Global field is 100 (staying in compliance with the maximum field limit for content types, i.e. 100).
The maximum number of Global fields that can be added in a single content type is 25.
The maximum instance limit set for a Global field that has been marked as "Multiple" cannot exceed 100.
A content type and a Global field cannot have the same name.
Nesting of Global field is not allowed. This means that you cannot add a Global field within a Global field.
Global fields do not support the use of labels.
Global fields do not support the use of field visibility rules.
Global fields do not support the use of non-localizable fields.
Only the stack owner, administrator, and developer can create Global fields.