Hi!I want to make a website and don't know which one to use.
Wordpress is better for SEO but it's to simple...
Joomla is more advanced but not to good for SEO.
I have no idea where you got this information from, but it's incorrect.
Some people like to use wordpress as a CMS, but it's not built to be a CMS. Joomla was built to be a CMS and does a pretty good job.
So to decide which one is best for you comes down to what you need to be able to do.
If you tell us what that is, we can give you advice on the best one for you.