Forwarding without www to www

I am using version 10.4.32 and I am not very used to typo 3.
All is working fine with but when I just use without the www there is an error shows up.
I found the section forwarding in the backend, but I have no idea how to use it?
Hope for help.

I don’t think that TYPO3 is the way for such a low level redirect. (why start all the PHP for something which can be done much earlier.
At stackoverflow you can find a solution without PHP.

Hi Bernd,
Thank you for your answer.
I do understand this solution, but in this case the website is a company website where I do have the login to typo3 but I do not have access tthe webserver. So I thought if I can realize within the CMS I wont need the hoster to make the changes.

I don’t think that missing rights for you justify a bad solution.
Either you have access (by server-administration-tool or editing a .htaccess file) or that service must be included in hosting fees. And it’s a one-time change which means not much work.