When I try to save something or rename a file/folder it say this error " Read-only file system" or run something as root in the terminal it say this error

sudo: unable to open /var/lib/sudo/"My User

First, run this command with sudo permission:

sudo fsck -n -f
Then reboot the machine.

There are many filesystems out there for Linux. Each of the filesystems has its use cases, pros, and cons. You may have a hard time deciding which filesystem to use. In this article, the Ext4 and the Btrfs filesystem are compared.