Atlassian JIRA board displays issues from projects and provides a flexible and convenient way to view issues.
There are two popular boards in Atlassian JIRA
SCRUM Board – The teams which work in Sprints
KANBAN Board – The teams which have a continuous flow of work like support team and they want to manage and put a constraint on the work-in-progress items
Boards can be shared within the team and across other projects as well if appropriate permission is given.
You can have multiple boards in one project.