Hello, userhani.
Personalizing your forms is one way to delight your customers. I'm here to guide you with the process.
Are you trying to customize your sales forms? If so, you can easily do it by going to the Custom form styles menu. Here's how:
For more details, you can check this article: Customise invoices, estimates, and sales receipts in QuickBooks Online.
Another way to do this is to import a personalized template using Docx files. Please check this article for the guide: Import custom form styles for invoices or estimates.
If this isn't the case, are you trying to customize your expense forms instead? We can only turn on a bunch of options for them, such as adding custom fields for purchase order. Here's how to do it:
Our developers might be planning on adding more options to customize your expense form in the future. You can check out our QuickBooks Blog for product updates in the meantime.
If you need help with other tasks in QuickBooks Online, we have a variety of content and articles to help you get started. You can browse them here.
I'm always here to offer help, so don't forget to visit this thread if you have other questions with QuickBooks Online.