¿Como Esta? vs ¿Como Estas?
Está and estás are two forms of the verb estar which is one of the verbs for 'to be'. Está is the usted form of the verb--that is, it is used to address people formally--and estás is informal; it is used with your friends, anyone you would address as tú. Esta is also the third person, and so can be used to talk about others. For example, ¿Cómo está?" can also mean, "How is he?"
What is the difference between esta and estas?
¿Cómo estás? means "How are you? (informal, with friends)
¿Cómo está? means "How are you? (formal)
Remember to use the accents!!
The usage depends on the person with whom you are speaking. For example with a friend you might use the tú form and ask ¿Cómo estás? With someone older or in an authority position you might use the usted form and ask ¿Cómo está?
Since we don't know each other I would ask you, ¿Cómo está?