Install phpmyadmin in Ubuntu 20.04

Here is how to install phpmyadmin on Ubuntu 20.04
References: Practical Ubuntu Linux Server for beginners

We need fist to have mysql-server installed, where phpmyadmin will store its data. For this reason we will run:
sudo apt install mysql-server

Then some libraries for the functioning of phpmyadmin as well as the phpmyadmin package:
sudo apt install phpmyadmin php-mbstring php-zip php-gd php-json php-curl php libapache2-mod-php
Note: if there is a problem in the installation you can Ignore, or Abort the configuration of phpmyadmin.

Let's now go and login inside of MySQL as root:
sudo mysql -u root 

or if you already have password/user then: login with: sudo mysql -u user -p

Next we will adjust the MySQL root password, as well as its method of authentication:
ALTER USER 'root'@'localhost' IDENTIFIED WITH mysql_native_password BY 'password';

Optional: 

Configure Apache in order to serve phpmyadmin (if not already done by installation of phpmyadmin): inside of etc/apache/conf-available/ we create the following phpmyadmin.conf file:

Alias /phpmyadmin /usr/share/phpmyadmin
<Directory /usr/share/phpmyadmin/>
   AddDefaultCharset UTF-8
   <IfModule mod_authz_core.c>
      <RequireAny>
      Require all granted
     </RequireAny>
   </IfModule>
</Directory>
 
<Directory /usr/share/phpmyadmin/setup/>
   <IfModule mod_authz_core.c>
     <RequireAny>
       Require all granted
     </RequireAny>
   </IfModule>
</Directory>

Lastly, we need to activate the above configuration file with:
a2enconf phpmyadmin.conf
and then restart the apache2 service to reload and accept the changed configuration:
sudo systemctl restart apache2.service

Now is time to open up in the browser to: http://127.0.0.1/phpmyadmin
and use the combination that we already set: root / password

Congratulations and enjoy learning !