DevOps is software development with operations. A company has its own needs to develop the software. A DevOps engineer understands the needs. He/she make a design for the software. Now the developed software is sent for its verification. Any bug or issue found is fixed. Bug is fixed on testing. The product is ready for its marketing.
Database designers, architectures, programmers etc. play an important role. The project can take a few days or months. It depends on size and quality of the app.
DevOps is of 2- types: waterfall and agile or scrum process. The waterfall process is the older one. It takes more time than the agile. Also, one cannot skip a step in between. While scrum process is faster and time efficient.