How to get List of all mounted filesystems on the Linux system?

The mount command mounts a storage device or file-system, making it accessible and attaching it to an existing directory structure.
The umount command “unmounts” a mounted filesystem, informing the system to complete any pending read or write operations, and safely detaching it.

Syntax: mount
mount [-lhV]
mount -a [-fFnrsvw] [-t vfstype] [-O optlist]
mount [-fnrsvw] [-o option[,option]…] device|dir
mount [-fnrsvw] [-t vfstype] [-o options] device|dir

Syntax: umount
umount [-hV]
umount -a [-dflnrv] [-t vfstype] [-O options]
umount [-dflnrv] {dir|device}…

The standard form of the mount command is:
mount -t type device dir
This tells the kernel to attach the filesystem found on device (which is of type type) at the directory dir.

following command to get List mounted files-systems on system:
mount | column -t

This gives you list of file system on your system.