Welcome to Community, bfc9545. I'll share information about how the font size that appears in QuickBooks Desktop works.
Currently, there's no option to change the font size while you're in the account register in Quickbooks Desktop. Since the system runs off of your computer's DPI (Dots Per Inch) settings, it only changes the display settings or adjusts your view preferences in QuickBooks.
Here's how to change display settings in QuickBooks:
Close QuickBooks Desktop.
Open the Windows Start menu.
Type "QuickBooks" into the search. Then, right-click the QuickBooks icon.
Choose Open file location. From the folder, right-click the QuickBooks.exe file and select Properties.
Go to the Compatibility tab.
Select the Disable display scaling on high DPI settings checkbox. You can also select Change high DPI settings. Then, Override high DPI scaling behavior.
Hit Apply and OK.
Then, you can follow the steps below to adjust your view preferences in QuickBooks:
From QuickBooks Desktop, go to the Edit menu. Then, select Preferences.
Click Desktop View from the list and choose the My Preferences tab.
In the View section, select the One Window option.
Once done, close and reopen QuickBooks and your company files to see the changes.