I'm not sure exactly what you're asking, but here goes...
A PC disk should be readable on the HD Amigas (4K/1200) without any modifications, since this is what the HD mode switch is for. If you're having problems with a standard 1.44MB format, try turning off the unformat feature with:
C:\> format a: /u
Now, if you're asking how to use the 1.44MB disk as a 720K, or using an actual 720K, then you'll need to cover the HD detect hole on the disk (to fool the drive into thinking it's low density), and issue the following:
C:\> format a: /f:720 /u
Both these commands assume your floppy is in a:.
If you're trying this on the Amiga side, then you'll just use the device name of PC0: or PC1:, like so:
WorkBench:> format PC0: NAME whatever NOICONS
You can also click on the PC0: icon and use the drop-down menu to format it.
HTH...
banzai
