The file system that is compatible with all three major operating systems (Windows, macOS, and Linux) is FAT32.
While other file systems like NTFS and HFS are supported only by specific OSs (NTFS primarily by Windows and HFS primarily by macOS), FAT32 can be read and written to by Windows, macOS, and Linux. However, it’s worth noting that FAT32 has a file size limit of 4 GB, which might be a limitation for some users.