Va is the il/elle/on form of the verb aller, which means to go.
Literally, ça va ? is something like Is it going? or Is that going?
But in real French, it is a very common expression used to ask how someone is doing.
So even though the literal grammar comes from aller, you should learn Ça va ? as a fixed everyday phrase.
Grammatically:
So the structure is just a statement turned into a question by intonation and the question mark:
French often makes informal yes-no questions this way: same word order, but with a questioning tone.
It is informal to neutral and extremely common in spoken French.
You can use it:
It is friendly and natural, but not especially formal.
If you want something more formal or more explicit, you might say:
Very common answers are:
A very typical exchange is:
Yes, very often.
Without question intonation, Ça va. can mean:
Examples:
or
So punctuation and tone make a big difference.