You can merge only two accounts at a time, and both accounts have to be the same type of account.
How to Merge Accounts in QuickBooks
If you have two accounts with the same details, QuickBooks allows you to merge such duplicate accounts. This will delete one of the existing accounts and move all the data to another account you want to keep. To merge accounts in QuickBooks, you are required to open the List menu -> click Chart of Accounts -> click the Account button to choose the account you will not use anymore -> select Edit to add the same account name you are merging with. Once the details of both the accounts are matched, click the Save & Close button and confirm the action.
