To Delete a Column, select that column and click Delete.
Deleting a Column may have potential affects on other objects in the Schema.
All Views and Indexes that reference the Column will remove their reference to the Column.
If that View/Index's last reference is removed, the View/Index will also be deleted.
Due to the free text nature of Custom View Columns, references to deleted Columns will not be removed and are your responsability to fix.
Due to the free text nature of Functions, Stored Procedures and Triggers, references to deleted Columns will not be removed and are your responsability to fix.