Hi How do I add a manual expense into my account ? An expense that didn't come out of my business account?

Welcome to the Community, jarna-everdaisy!

Is this expense paid with personal account? If so, yo can record them in QuickBooks using a journal entry and use the owner's equity account and the expense account. Here's how:

1. Click on the +New button, click on Journal Entry.
2. On the first line, under Debits select a expense account for the purchase, and enter the amount.
3. On the second line, select Owner's or Partner's equity account, and amount in the Credit line.
4. Click on Save and close.

When your company is ready to pay you for the reimbursement, record them as a cheque or expense transaction. 

1. Click on + New.
2. Click on Expense.
3. Select a bank account to use to reimburse the personal funds.
4. In the Category column, select Partner's equity or Owner's equity.
5. Enter the amount of the reimbursement.
6. Click on Save and close.

That's it. You've now recorded the expense in your QuickBooks Online. You can check this link to learn more about Pay for business expenses with personal funds.

Drop by again if you have concerns about your QuickBooks Online. I'll be right here to answer them for you.