Should you for some reason need to install a Wordpress-site, here are the basics:

1) Install packages, run:

apt install libapache2-mod-php apache2 php-gd php-mysql php-zip mariadb-server -y

2) Secure MariaDB, run:

mysql_secure_installation

and go through the wizard:

<Enter> to set password if empty
N for no Unix socket
Y to change root pass
Y to remove anonymous users
Y to disallow remote root login
Y to remove test db
Y to reload privilege table

3) Create a user, a database and set permissions

Connect to MariaDB, run:

mysql -uroot -p

Create a user, run:

CREATE USER 'wordpress'@'localhost' IDENTIFIED BY 'V3RY_S3CR3T_P4SSW0RD';

Create database, run:

CREATE DATABASE wordpress;

Set permissions for database and user, run:

GRANT ALL PRIVILEGES ON wordpress.* TO 'wordpress'@'localhost';

Apply changes, run:

FLUSH PRIVILEGES;

Exit from MariaDB, run:

quit

4) Download latest version of Wordpress

cd /var/www/html/ && wget https://wordpress.org/latest.tar.gz

5) Extract Wordpress archive

tar xzf latest.tar.gz

6) Move files from newly created "wordpress"-folder and delete it, including the default index.html from the Apache install

mv wordpress/* . && rm -rf wordpress/

7) Set permissions to Wordpress-install, if not already properly configured

chown -R www-data: /var/www/html/

Browse to the webserver and complete the installation wizard.