Create a system account www-data with the same UID and GID

usracc_wwwdata.sh

# Create www-data account
useradd -s /sbin/nologin -d /var/www -r -M -U -u 777 www-data

# Set the ownership to www directory
# chown -R root:www-data /var/www
chown -R www-data:www-data /var/www

# Set permissions of child files and directories inside the www directory
find /var/www -type d -exec chmod 2775 {} +
find /var/www -type f -exec chmod 0664 {} +

# Append nginx user to www-data group
usermod -aG www-data nginx

# Append mysql user to www-data group
usermod -aG www-data mysql

# Check info
id www-data && id nginx && id mysql
ls -la /var | grep www-data