The owner of the directory where you want to put the file is probably root (or possibly apache). To put the file there, you have to become superuser.
If you’re in KDE, the easiest way to do that is to use System -> File Manager (Superuser Mode).
Another way to do it is to be a member of the group for the directory where your Web pages will go (using File Manager (Superuser), once again). Right-click on the folder and check the permissions and ownership. Then use Yast -> User Management to make sure that you are a member of that group as well. One common approach is to use the group “wheel” or “apache.” Make sure anyone in the group can write to that directory and you’re covered.
DO NOT give in to the temptation to make that directory world-writable (ie, anyone can write to it). DO NOT make that directory a member of the “users” group, either. This is a security feature built in to Linux. It’s a pain when you’re copying files, but it makes it much, much more difficult for a Bad Guy to tamper with your pages, too.
> I have recently setup an Apache server and i am unable to copy a
> index.html file to the directory to check if it worked.
> It says error, then something about “i don’t have permissions”.
This is because you don’t have permissions. Usually, the package
apache2-example-pages should be installed, which includes a sample
“It works!” page.