Azure DevOps can be deployed on any Azure environment and includes Azure Repos, Azure Pipelines, Azure Test Plan and even integration with GitHub Enterprise.
Azure DevOps Server is available in Express edition for an team of developers from 1 to 5 at no cost.
You can download Azure DevOps Server from https://go.microsoft.com/fwlink/?linkid=2041267&clcid=0x409, while requirements are available here https://docs.microsoft.com/tfs/requirements
- Installation Guide: https://docs.microsoft.com/tfs/install/get-started
- Upgrade Guide: https://docs.microsoft.com/tfs/upgrade/get-started