You can simply manage allow_url_fopen and allow_url_include function by editing php.ini file on your server. You can enable it if these function is disabled in php configuration file.
These function may be disabled in the php configuration file on some shared hosting server. You can simply manage these function by creating custom php.ini file under your public folder.
On Dedicated Server
Open the /etc/php.ini file and add or changes below two lines:
#vim /etc/php.ini allow_url_fopen = On ...... allow_url_include = On
Restart web server.
# service httpd restart
On Shared Hosting Server
Create or open php.ini file under the public directory of your domain and add the following two lines to enable these function.
allow_url_fopen = On ...... allow_url_include = On