Greetings.
I recognize you need to merge or transfer data. I'm here to provide more details about your concern about QuickBooks.
If you are using QuickBooks Self-employed, merging files from QuickBooks Desktop is unavailable, especially for older data. However, If you mean migrating data from QuickBooks Desktop to QBO, we need to restore company files from 2013 to 2021 data, then convert them to QBO.
In QuickBooks Online, another workaround is to utilize a third-party application that does the process for you. Visit this link and find the best app for your business: QuickBooks App Center. However, we're unable to have this option in Self-Employed since it is a standalone accounting software.
Please come back here to the Community so we can provide you with more options for migrating files in QuickBooks. Enjoy your day.
