That is how you can achieve it!
Combine Outlook Inbox
Note: This procedure assumes POP3 accounts. If you are creating new accounts using the auto-detect feature, you can combine the inbox once you are done with creating them. If you have already created the accounts, you can still combine them in Outlook.
To combine Outlook Inbox: Now, in the Change Folder dialog box, select Outlook and then Inbox. If you wish the mail to be delivered to a custom folder, click New Folder to create a new folder. If you wish to use a new PST file for email, you can select New Outlook File. But since your contacts, calendar, etc., are already stored in outlook.pst. It is better to choose Outlook -> Inbox as it will save time on backing up files (See the last figure below). Once you have selected the folder you wish, click OK. Repeat above steps for each email account inbox you want to combine. Close the Account Settings window
Following the above procedure, you can close the additional files that were created by MS Outlook for different email accounts that you have now combined – as the new mail will be delivered to the folder you selected in step 5.
This explains how you can combine Outlook inbox in version 2021/2019. If you have any doubts, please drop a line below.
Can you combine inboxes in Outlook 365?
You cannot, as the option to change the folder is missing. Instead, you can use the search folder to see recent emails from all inboxes. Click on the Search box on top of Outlook, and search for All Mailboxes. Once it appears, click on it, and then click on the Unread option. Now you have a view where all unread emails appear in one place.
How do I make an email move to a specific folder when it arrives?
You will need to create rules for this. Based on the subject, email, from, to, and other email-related data, any email can be moved into a folder when it arrives. You can apply it to a single mailbox or all of them.