Cannot add .htaccess in /wp-includes/

Hi All,

I have three websites:
fundatii.afacereamea.ro
vindecare-cancer.afacereamea.ro
agro.afacereamea.ro

where I cannot add a .htaccess file using the hardener option from Defender.

My opinion is that there are some permissions and group/owner problems.

Please help me!

Daniela