Barrier is a part-open source application that allows multiple computers to share a single keyboard and mouse set. This allows you to have multiple computers attached to separate monitors, all of which can be worked on with only one set of peripherals. Barrier works by running a server on the computer that the keyboard and mouse are connected to. This server then talks to clients that are installed on the other computers via SSH.
Barrier is working across different Operating Systems (MacOS, Linux, Windows) so you can download it very easily using .exe for windows and .dmg for mac and command line in linux.
Download from this link
And from command line ubuntu

sudo apt update
sudo apt -y install barrier

Now, I took the IP from server to client.

Maybe you would face this error

ssl certificate doesn't exist: /path/to/SSL/Barrier.pem
We need to install openssl within our server and client, so on windows:
From CMD winget install openssl or download it.
On linux:
From terminal sudo apt update
sudo apt update
openssl version

Then on both Operating Systems

cd  "path to your SSL"
mkdir -p Fingerprints
openssl req -x509 -nodes -days 365 -subj /CN=barrier -newkey rsa:4096 -keyout Barrier.pem -out Barrier.pem
openssl x509 -fingerprint -sha256 -noout -in Barrier.pem > Fingerprints/Local.txt
sed -e "s/.*=/v2:sha256:/" -i Fingerprints/Local.txt

Then restart your Barriers