I would like to delete the www-ssl service that I accidentally set up before. However, I don’t know if this is possible. I don’t see this option anywhere. I can only disable it. Can you help me?
You can not remove anything on that section.
You can only disable the services.
Before you enable the services, the services are already bundled with RouterOS, but disabled.
As long as its NOT green that is good = disabled (greyed out)
Also make sure you do the same thing at the firewall settings for ports…
…
What do IP Services have to do with Service Port (connection-tracking helpers)?
(In RouterOS 7 you can’t disable some of them, for example dccp, sctp and udplite)
You don’t know how the internal devices are configured and, by suggesting this, it can have negative consequences… 
Not all networks are configured like those in your home… 
The right question, based from OP screenshot and topic question, is:
Why he have enabled all services.
I do not think he use, for example, ftp, api or telnet…