That’s not possible I’m afraid. You could buy, for example tech4file.com, and park that on top of tech4file.ml so they are linked to the same directory.
Any subdomains of tech4file.com will have to be added manually as subdomains. Those subdomains will then get their own directories, and you’ll need to move the files from the tech4file.ml subdomains yourself. That’s the first option.
If you want a second option: you could upgrade to premium hosting first, and then do the migration to your new domain (you could include the new domain with the hosting plan if you want). Premium hosting lets you link any (sub)domain to any directory on your account, so you can link the .com subdomains to the folder of the .ml domains.