Vouchers were issued by the previous owner, we have had to honour these as they are now our clients how do I process these on QB

Great to see you in the Community, @elizabethmcmilla. I can share some steps in recording this item in QuickBooks Online (QBO).

Creating a line item such as Service or Stock for the voucher is good for tracking. Then, include this on the sales form once there is a presented voucher.

However, if you want to write it off in the future, I'd recommend speaking with your accountant. They can also give you some advise on how to treat vouchers and balance your sales to avoid earning less in the future.

Now, going back to recording the voucher, you can follow the steps below:

1. Go to the Sales menu and select Products and Services.
2. Click New and choose if you want to record it as Service or Stock.
3. Fill in the details in the boxes and select Save and close.

Once done, you can now create a Sales form. For line item vouchers, calculate the pre-tax amount of the other services or stock. Then, enter a negative amount in the Amount column. I've got some sample screenshots below:

For more information about managing your Sales and Stocks in QBO, you can check out this article: Add product and service items to QuickBooks Online. It contains steps and tips on how to track your items easier.
 

Moreover, to get sales insights in the future, you can run these reports below:

• Sales by Product/Service Summary
• Sales by Product/Service Detail
• Stock Valuation Summary
• Stock Valuation Detail
• Stock Take Worksheet

Here's the reference about the reports' descriptions: Use reports to see your sales and stock status.
 

Please let me know if you have any additional questions or concerns. I'm always around to lend a hand. Take care!