how do i increase the max_input_vars

Hello,

My domain name is : maisonmohs.com

And I use : - Hosting OVH Perfomance

I'm trying to increase the max_input_vars because i need to add a "top-bar" menu and it doesnt show up. I was looking for documentation and it says that i need to add this line of code in my php.ini or .htaccess, however when im trying to add it in .htaccess the web gives me a 500 internal error and i can't find the php.ini file. Also, how do i restart the webcloud? If i apply a change i will need to restart but i dont find the option.

// Documentation: https://goya.everthemes.com/help-center/menu-items-or-mega-menu-not-saved/