Hello @Teresa_Lejman,
Welcome to the Asana Forum.
The Asana inbox is engineered so that you actually are supposed to consume the notification and then archive it, it is not the place where you want to store or organise information. Think of the notification centre in your phone. It is kind of the same principle, you clear those notifications too.
For action items, depending on the task, you either want to assign the task to yourself or you could create a follow-up task either by using the dedicated button or by adding a subtask with the name “follow up” and assigning this to yourself. These will show under My Tasks.
Action items are managed from My Tasks. You can organise My Tasks any way you want it, so you can group information in the way that makes most sense to you there.
Ideally at the end of the day, your Inbox has zero notifications.
This article and the short video in it, give you a good overview of how the Inbox should be used:
And I would also suggest get some inspiration from this other article on My Tasks:
Cheers,
Rosario