https://docs.github.com/en/authentication/connecting-to-github-with-ssh/adding-a-new-ssh-key-to-your-github-account

Setup

Install git

sudo apt-get install git

Setup user and email

git config --global user.name "Your Name" git config --global user.email ""

Generate a new SSH Key

ssh-keygen -t ed25519 -C "your_email@example.com"

Output

>>$ ssh-keygen -t ed25519 -C "your_email@example.com"
Generating public/private ed25519 key pair.
Enter file in which to save the key (/home/user/.ssh/id_ed25519): /home/user/.ssh/github
Enter passphrase (empty for no passphrase): 
Enter same passphrase again: 
Your identification has been saved in /home/user/.ssh/github
Your public key has been saved in /home/user/.ssh/github.pub
The key fingerprint is:
SHA256:dfghjkl;lkjhgfghjkl; your_email@example.com
The key's randomart image is:
+--[ED25519 256]--+
|                 |
|        2222222  |
|       11111111  |
|      .33333333  |
|   234234o=*     |
|      . o=**+    |
|       ..+==oo   |
|     23423433343 |
|     1213242*rr  |
+----[SHA256]-----+

Copy public key to github

1. Open Settings
2. Click SSH And PGP
3. Click New SSH Key
4. Get the key material WARNING This will show your credentials in clear text. Run this when no one can see your screen and complete until the end cat ~/.ssh/github.pub

Output

>>$ cat ~/.ssh/github.pub 
ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIPKpa91hiCHWQ/mpNdad+aGSzX5BftyUDNl6YkbgcQQm your_email@example.com

5. Past the material into the box
6. Click “Add SSH Key” and confirm it is correct
7. Remove the key from the terminal clear

Configure github as a host in ssh

cat << EOF >> ~/.ssh/config

Host github.com
    HostName github.com
    User git
    IdentityFile "~/.ssh/github"
EOF

End