Cannot add attributes to data extension
Occasionally, as a Salesforce Marketing Cloud administrator, lurker, practitioner, or bystander, you encounter a seemingly simple yet potentially time-consuming task—adding attributes to a data extension. While it may sound straightforward, the process is not always as simple as it appears.
When adding or editing data extension attributes in Salesforce Marketing Cloud, you may face a challenge: edit/add options could be concealed, possibly set by another admin user. This feature restricts users from altering any data extension settings. To reveal the edit options, navigate to Contact Builder, click on Manage Control Policy Settings, and enable ‘Allow users to modify/add attributes
Hope this information saves you some of your precious time as a platform administrator.