correct html tag on localhost but sanitized in web even same php code and database

I'm trying to figure out a strange issue I stumbled on:

Locally and on external server I use the same web environment thanks to Ansible and Vagrant.

I use Ubuntu, Apache Webserver, MySQL, PHP 7, Codeigniter 3.

On the edit form I see on localhost correct HTML tags.

But when I open the same page from the cloud (an external Webserver) the HTML tags are sanitized on Chrome and Firefox.

What's the cause of this behaviour and how can I prevent the sanitized html tags?