Welcome and thank you for posting here in the Community, @isaachm.
To give you the right amount of information and assist you further, may I know what specific area and transaction you're working with QuickBooks while you're asked to select an account even if you've already entered an account name?
It's possible that you've chosen the incorrect account reason that you're asked to select an account again. Make sure to select the correct account when creating transactions. If you're creating a check, select an expense account, if you're creating a bill, you can either select expense or accounts payable and so on.
However, if you're referring to something else, feel free to add a comment below. Have a good day!
Welcome to the thread, @Lacylay81. Let me help you save journal entries in QuickBooks Online (QBO).
When creating a journal entry, it needs to have an account for the debit and credit accounts so you won't encounter an error "Select an account for this transaction."
Then, ensure that the amount has the same total balance in the Credit column on one line and the Debit column on the other. For more details on making a journal entry, see this article: Create journal entries in QuickBooks Online.