Can I add multiple sub accounts under a parent account, for example under Utilities I think I should have separate accounts for gas, electric, telephone and water?

Hi d-v-d,

Using sub-accounts is a simple way to unlock advanced categorization for your accounts. Keeping things organized enhances the information shown in your reports and makes it even easier to keep your books balanced. QuickBooks Online is all about giving you control to customize the experience to your liking, and that includes powerful management for your chart of accounts. I'll be happy to help you get started. 

You can create any number of sub-accounts under a single parent account. Each of these sub-accounts can also have any number of their own sub-accounts up to five levels deep. It's just a couple simple steps to set this up:

1. Go to Settings ⚙ and select Chart of Accounts.
2. Select New. 
3. Select the account type and detail type. You can learn more about account types and detail types if you have questions.
4. Select Is sub-account and then enter the parent account.
5. Give your new subaccount a name. You can also add a description.
6. For the as of date, tell QuickBooks when you want your account to start. Then add the Balance in the account as of the date you choose.
7. Select a Default Tax Code. Note: Only some account types need this, like bank, credit card, asset, and liability. If you need help, you can learn more about opening balances.
8. Select Save and Close.

Check out this great article for additional details: Create subaccounts in your chart of accounts in QuickBooks Online

With this, you're all set to make the most out of your reports! Let me know if there's anything else I can help you with.