How to mark dependent fields while updating rest of the fields?

1. Can we mark standard fields as dependent fields?
2. How do I add a field dependency in a change in Salesforce?

Can we mark standard fields as dependent fields?

Yes you are correct a standard field cannot be dependent field.

How do I add a field dependency in a change in Salesforce?

In the Change Sets list, click the name of a change set. Click View/Add Dependencies. On the Component Dependencies page, select the dependent components you wish to deploy and click Add to Change Set.