"Multiple" would have to mean "three at most" on the x10Hosting Free Hosting system. For a combination of idiot-proofing and catastrophe mitigation,¹ your primary domain name here must be an x10Hosting-provided subdomain (in this case, beauty.x10host.com). That leaves you with one "parked" domain (which is a sort of alias for your primary domain, and will always point to the same place) and two "add-on" domains (which are normally pointed to subdirectories of your primary domain, but they can also be pointed to your primary domain if you prefer).
Since x10Hosting (Free Hosting) is not a domain provider (x10Premium is), you wouldn't so much be
transferring your domains as pointing your existing domains to your Free Hosting account. If your existing domain provider can't provide a way to do that for you, you may have to transfer your domain to another domain registrar. (Hosting companies are required, in the US at least, to allow transfer of domains, but not to maintain DNS records for "foreign" domains. That means that they have to allow you to use the domain elsewhere, but they don't have to let you use their servers to point to someone else's servers. Most will, since reputation matters, but smaller "mom and pop" places might take things kinda personal.) All you need to do is to use x10Hosting's nameservers, ns1.x10hosting.com and ns2.x10hosting.com as the nameserver entries for your domain records (there should be a place to enter them on your domain control panel). Once the nameservers have been set on your domain, you can enter the domains as a parked domain or as add-on domains in your Free Hosting cPanel (
the instruction here might be of more help).
If you need to use more than three external domains, then Free Hosting isn't going to work for you; you would need to upgrade to a
Premium account.
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¹ x10Hosting used to allow users to change their primary domain to an externally-sourced domain if they wanted to. Well, people who forgot to renew their domains or to failed to follow the terms of service of their free domain providers would lose all access to their accounts from time to time. And when a once-popular free "domain" provider, co.cc, decided to cease offering free domains (due to continuing abuse, ISP blacklisting and spamhaus listings), the same thing happened to people who
were being careful with their service. To prevent that from happening in the future, you are now required to have an x10Hosting-provided subdomain as your primary domain.