Answer:
use fat32
FAT32 is regarded as the default file system for external drives, especially the removable USB flash drives and SD memory cards. It's the most compatible file system that can be used on major devices and operating systems like Windows and macOS. So, the advantage of using FAT32 is portability.
However, FAT32 has some disadvantages, or let's say limitations as well. First and foremost, if you use a single file over 4GB in size, you'll need to convert FAT32 to NTFS or exFAT; What's more, due to the manufacturers' specifications, FAT32 can only be used to format drives between 2GB and 32GB, and that's why native tools on Windows have that limit, too. When you try to format a USB drive over 32GB in Windows Explorer, there is no "FAT32" option at all.