How to delete default data file in outlook?

Question

Outlook

The essence of the problem is this - We add the imap account to Outlook, but Outlook also creates its own "Outlook Data File". Which cannot be removed. So, the letters are partly located in the folders of the imap account and partly in the folders of this data file. Why is this happening, and how can I make sure that if I send a letter, it gets into the sent imap and not into the "sent" outlook data file? And letters get in different ways, some fall into the sent imap, and some fall into the data file. What does it depend on?

How to link Outlook data file and imap account into one? So that on the left in the panel there was no this Data File, but one account?