Even though I am using mxlinux but you can use these commands to install XAMPP server almost in any Linux distribution.
Download XAMPP from apachfriends.org
open Downloads directory, right click anywhere and choose open terminal here.
now enter this command REPLACE xampp-linux-x64-7.3.7-0-installer.run WITH YOUR XAMPP VERSION
sudo chmod 755 xampp-linux-x64-7.3.7-0-installer.run
Run installer
sudo ./xampp-linux-x64-7.3.7-0-installer.run
Start XAMPP server
sudo /opt/lampp/lampp start
Stop XAMPP server
sudo /opt/lampp/lampp stop
Restart XAMPP server
sudo /opt/lampp/lampp restart
Uninstall XAMPP server with this command.
sudo /opt/lampp/uninstall