What is the best way how to make form which store data in more than one list/ library?

TomasG  Hi there!  I'm not exactly sure I understand the complexity of your requirement.  However, I have created forms where -- when you create your record, you can include attachments, then when you save the record the attachments are moved into a specific document library.  Then, I later filter the documents to display them on another screen within the PowerApp.  

Here is the discussion and link to April Dunham's tutorial on moving attachments. 

https://powerusers.microsoft.com/t5/Creating-Apps/Moving-PowerApps-Attachments-to-a-Document-Library/td-p/236319