Organize all of your tasks in lists. Put lists together in a namespace to keep related stuff grouped together.
Vikunja lets you easily share a list or a namespace with another user or a whole team! You can also assign tasks to people so everybody knows who's working on what.
You can show your tasks in the classic list view - each task underneath each other. Or you can use the Gantt view to get a time overview. Or Table view to show all details you need. Or Kanban if you want that birds-eye view of the status of all current tasks.