HOW DO I ENTER PAYMENT WHEN CLIENT HAS TAKEN OFF WHAT i OWE THEM ?

Hi, Chemquad. Let me ensure you record your invoices in QuickBooks Online (QBO) properly.

Before we begin, if you haven't yet, let's make sure we create a bill transaction for £20 first and an invoice transaction of £100.

After this, let's go ahead and create a journal entry to offset the invoice with the lower value, the £20. Follow the steps below:

1. Select + New and select Journal entry.
2. For line 1, select Debtors (Accounts Receivable) in the Accounts column.
   1. Enter the credit amount in the Credits column (£20). 
   2. Enter the name of your client in the Name column. 
3. For line 2, select Creditors (Accounts Payable) in the Accounts column.
   1. Enter the debit amount in the Debits column (£20). 
   2. Enter the name of the supplier in the Name column
4. Click Save to save the journal entry.

Once done, we can pay the bill and the invoice by following the steps below.

Bill:

1. Go to Expenditures. Select Bills.
2. Toggle to the Unpaid tab
3. And then select the £20 transaction. Then click Mark as Paid.

Invoice:

1. Go to Sales. Then select Invoices.
2. Open the outstanding invoice and select Receive payment. 
3. Use the journal to settle the outstanding amount, leaving the remaining balance to be paid later. 

Furthermore, you can personalize the appearance and layout of your sales forms. Here's an article for future reference: Customise invoices, estimates, and sales receipts in QuickBooks Online.

If you have additional questions about recording invoices, comment on this thread. I'll be around in the Community, ready to assist you swiftly.