Hi Takanobu,
It is possible to show a header and a list of details on one page.
Your header object should be the Page parameter for a Dataview and in the dataview you place a listview for your details object (over association). Your user could add extra detail objects to the header through an button with a microflow.
It is not possible to pass the header object and the list of detail object at once in a microflow, but you can pass the header object and your first action in the microflow would be a retrieve by assocation to get the list of detail objects.
Hope this helps.