If you just mean the default format JMP sets to the imported columns, I think JMP might be using your operating systems format. Using JMP > Set JMP Column Properties > About the Column Info Window > Numeric Formats
International Formats
If you are importing or entering data that contains formatting that is specific to country standards, you might need to ensure that your number formats are interpreted correctly. On Windows, access the Control Panel’s region and language option, and select the country for which the number should be formatted. On Apple macOS, from the Apple menu, select Language & Region > Formats, and select the correct country. On later versions of Apple macOS, this option might appear under System Preferences > Language and Region.
You could create workflow for importing the data with re-format or maybe create a tag which would set the format when you use the said tag.
-Jarmo