Hello there, @Jane Xiao.
In QuickBooks Online (QBO), we can customize your template in Word and verify that your template fields match correctly with QuickBooks fields. Then, determine the text or fields that don’t change with each print. You may follow the steps in this article to be guided in reuploading and mapping your template: Import custom form styles for invoices or estimates.
Additionally, you can follow Fiat Lux - ASIA's answer.
I'm also adding this article to learn how to upload and add logos to your invoices, estimates, and sales receipts in QuickBooks Online: Customise logos on sales forms.
Please don't hesitate to add a comment below if you have any other questions. Have a great rest of the day.
