Ubuntu can read and write disks and partitions that use the familiar FAT32 and NTFS formats, but by default it uses a more advanced format called Ext4. This format is less likely to lose data in the event of a crash, and it can support large disks or files.

Is Ubuntu FAT32 or NTFS?

General Considerations. Ubuntu will show files and folders in NTFS/FAT32 filesystems which are hidden in Windows. Consequently, important hidden system files in the Windows C: partition will show up if this is mounted.

What file system does Ubuntu 18.04 use?

In the Volumes section you can also see the description Contents: Ext4 which means that the partition is formatted as Ext4 which is the default Ubuntu filesystem format.