htdocs permission in ubuntu code example

Example 1: why i am not able to make a directory in htdocs folder in ubuntu

$sudo chmod -R 755 /opt/lampp/htdocs
$whoami
$sudo chown -R username:username /opt/lampp/htdocs

Example 2: why i am not able to paste anything in htdocs folder in ubuntu

sudo chown yoggesh:yoggesh /opt/lampp/htdocs
sudo chmod 777 /opt/lampp/htdocs