You may block access to your website from specific IP addresses using .htaccess file.
You need to create this file in your public_html folder and add these example lines:
order allow,deny deny from 127.0.0.1 allow from all
These lines will block access for all users using 127.0.0.1 IP address. Just change the 127.0.0.1 to the IP you want to block.
You can download the list of each country IPs from following link: https://www.countryipblocks.net/country_selection.php