The most important thing that you must understand is that these two are not parallel technologies. On one hand, Salesforce is a cloud service provider, on the other DevOps is a framework for building applications, especially for software development. You can use the Salesforce cloud service to implement one or all the DevOps principles.
If you wish to learn more about DevOps, visit DevOps tutorial and DevOps Training by Intellipaat.
To learn in-depth about Workflow in Salesforce, sign up for an industry based Salesforce Admin certification.