We're pleased you've reached out regarding the date format in QuickBooks, Marcelyn. To provide accurate and helpful guidance tailored to your situation, I need to gather a bit more information.
Could you please clarify which specific area of QuickBooks Online (QBO) you're trying to customize for the date arrangement? Please note that the program has different sections or data entry fields that contain or require dates. Knowing the exact location would help me provide an accurate solution.
What's more, QuickBooks doesn't have the option to set your date format with an uppercase for the month(dd/MM/yyyy), as you've mentioned. However, it does provide several formatting options to choose from, as listed below:
- mm/dd/yyyy
- mm-dd-yyyy
- mm.dd.yyyy
- dd/mm/yyyy
- dd-mm-yyyy
- dd.mm.yyyy
- yyyy/mm/dd
- yyyy-mm-dd
- yyyy.mm.dd
If you'd like to update your QuickBooks account to one of these date formats, you can follow the steps below.
- Go to the Gear icon and select Account and settings.
- Click the Advanced tab, then navigate to Other preferences.
- Hit the pencil icon to edit.
- Choose your preferred format in the Date format drop-down arrow
- Tap Save, and then Done.

I hope this information helps clarify the available date format options in QuickBooks. Yet, if I've missed addressing a specific area or if you're referring to something I haven't mentioned, please don't hesitate to let me know.
Your input is valuable, and I'm always here to help in any way I can. Please share any QuickBooks-related concerns you may have in the comments below. Your success is my priority!