In Jira Agile, Kanban and Scrum can really have access not just to one, but to all projects.
When you create a board, you can create it from a project or from a JQL query:
– if you are doing it from project, you can select multiple projects.
-if you are setting up from a query, then you would put something like: project = “A” or project = “B”
The one thing you will need to make sure of is that both project are using the same workflow or you will have trouble with status changes. If you are using the simplified agile workflow on them then you should be fine.
How to create JIRA Agile board, check the guideline – here.