You can call them both but the 'bud' is referring to the soft part that goes in your ears. The regular ones that go across your head and sit on your ears would be ear / headphones

They are earphones. Earbuds are the things that go into your ears that prevent other sounds from entering. Hope this helps :)

They are both correct, but earphones is more natural.

The usage is evolving as the devices evolve. "Earphone" is a general term for devices that play sound into the ear, which can only be heard by the person wearing them. It's quite an old term. It is the alternative to a "loudspeaker" or "speaker." "My wife doesn't like the music I like, so I listen on earphones instead of a speaker." "Earbuds" are a kind of earphone. Earbuds are very small earphones that fit tightly into the ear canal. "Headphones" are large headphones with a headband that completely cover the ear. And, finally, a "headset" is a combination of a pair of headphones and a microphone, for having a voice conversation, possibly over the internet.

You can call them ear buds or ear phones. Ear buds is the more specific name, ear phones covers a wider range such head phones, etc.