Approval workflow for Prospect Account

Summary:

Hi Team,

We have a requirement where we need an approval for any account that user creates in Sales as prospect and once the approval is provided then only it can be converted to Customer. We do not have CDM

Content (required):

Please suggest how can we achieve above use case.

Version (include the version you are using, if applicable):

We are using Sales, Service and AR

Code Snippet (add any code snippets that support your topic, if applicable):