WhenI make changes to my diagram of an identity is no way to synchronize itwith the table I have in the database or generate a script for that change, eg add a field in a table in the diagram and then somehow I synchronize that change to add that field in the database.
You have made changes in your model and need to apply the changes in your database.
Solution: Generate alter script in Toad Data Modeler.
Then you will have to use a third party software to execute the script in your database. E.g. if you use Oracle db, you can use Toad for Oracle.
How to generate alter script in TDM:
Open your model.
Open the Sync&Convert Wizard.
On page Select Right Side, click the Reverse Engineering Alias option and connect to your database.