How can i acces or make changes in the Libinput file?

[zenzen]

In case you are not overly familiar with the terminal, see this thread to see how to launch the file manager with elevated permissions:

Three ways to edit files and folders as root

1: Run nautilus as root. In the terminal type: sudo nautilus. Navigate to Computer. Some people say this is dangerous but I never had a prob. 2: Open Home and hit CTRL+L to open a location. Then type admin:// Then Enter. 3: Install nautilus-admin to get a right click option to open a file or folder as root. This is the most convenient and specific way. sudo apt install nautilus-admin

Do not get used to doing this. Use only when strictly needed, and then close it.