You will need check this article :
How To Point to DigitalOcean Nameservers From Common Domain Registrars

Configuration

Add Digitalocean domain records

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Open default.conf file

sudo nano /etc/apache2/sites-available/000-default.conf

Above the configuration:

ServerAdmin webmaster@localhost
DocumentRoot /var/www/html

Add:

ServerName barrouh.com
ServerAlias www.barrouh.com

Restart Apache:

sudo systemctl restart apache2.service