How can I increase the size of the type in the file info ?
You can increase the font size in some of the fields in File Info by right clicking inside the field and selecting Fonts>Show Fonts, but it's only temporary it seems, since closing and reopening the file info returns the font size to the default, whatever size that might be.
Can you post the screenshots?
Are these from the same Mac?
Same screen resolution?
What macOS are you using
Your screenshots don't show, but more than likely it's the difference between the screen resolutions of the two iMacs.
The older iMac had a lower screen resolution than the newer iMac, so everything is larger on screen.
You can play around with the different settings under System>Settings>Displays to get larger items on your screen.