Change ownership of single file :
sudo chown username:groupname path/to/file/filename
Example : sudo chown developer:www-data /var/www/html/info.php
Change ownership of multiple files of specific extension :
sudo chown -R username:groupname path/to/files/*.ext
Example : sudo chown -R developer:www-data /var/www/html/*.php
Change ownership of a directory:
sudo chown -R username:groupname /path/of/directory
Example : sudo chown -R developer:www-data /var/www/html/laravel