Field Validation or workflow? Next step field on opportunity page...

Hello Oracle community,

Hoping someone who has very good knowledge of CRM that can answer a question I have.

The next step field on the opportunity page has become a mandatory field by management. Basically, they want the sales rep to update this field when they update the opportunity.

They want the rep to start with the current date - and then the step. Currently this field is not a required field.

What is happening is the rep will create the opportunity and will either forget to put in the step or will put in the step without the current date. And when they modify the opportunity, they are forgetting to update the next step field leaving old data in it.