There are 4 core processes to organise a project in Azure Devops: Basic, Agile, Scrum, CMMI
Agile and Scrum are the more common processes used by software development team and provides adequate framework to express various situations that may be encountered during the project.
Agile components are Epic, Feature, User Story, Task with Issue for bugs.
Scrum components are Epic, Feature, Product Backlog Item, Task and Impediment for bugs.
Even though the elements are somewhat similar, the difference lies in the structure of these 2 processes. Scrum being tied to sprints where as Agile being run as a workflow with iterations.