Welcome to the Community, @Prostang.

I understand the importance of this feature when managing your invoices. However, this is unavailable as of the moment as mentioned by my colleague @Adrian_A. Meanwhile, you can try the suggestion raised by Fiat Lux - ASIA to get the desired time format for your invoice.

Also, I highly recommend visiting our QuickBooks blog so you can get current about the latest news and product developments. This way, you'll know if the feature you wish is now available in the new release. Here is a direct link that you can use: https://quickbooks.intuit.com/blog/.

Moreover, I don't want to leave you empty-handed, so I'll be providing you an article on how to customize your invoices in QuickBooks to get personalized details for it: How can I customize my invoices in QuickBooks Online?.

Please let me know if you have additional questions about managing your invoices in QuickBooks Online. Stay safe and have a good one, @Prostang.