Question: I have learned that when someone wants to know where a person comes from, one must ask: 

> 
> Woher kommen Sie?
> 
> 
> 

A lot of people have asked me: 

> 
> **Wo kommst du her?**
> 
> 
> 

or 

> 
> Wo kommen Sie her?
> 
> 
> 

Indistinctly. So the question is what is the difference?

Answer: 
The difference is in the meaning, but this can change by adding words.

The first phrase *Woher kommen Sie?* asks
more where you are coming in the moment. For example: *Ich komme gerade aus der Universität*. But it can **sometimes** also have the meaning of the second, depends on the context. So standard meaning: From where do you come in the moment?

In the other phrase *Wo kommen Sie her?* one asks about your origins, town or country. So standard meaning: From which town/country are you?

But the phrases can be modified. If I ask *Woher kommen Sie **eigentlich**?*, then it has the standard meaning of the second. If I ask *Woher kommen Sie **gerade**?* underlines the meaning, where do you come in the moment.

And if I ask *Wo kommen Sie **denn jetzt** her?*, the second has the standard meaning of the first.
While the *meaning* of the two forms is rather similar, they derive from different starting points.

> 
> Woher kommen Sie?
> 
> 
> 

The question word *woher* is asking for a place you came from and the *from* is included in that question word. The rest is rather simple, the verb is *to come* just signifying a movement.

> 
> Wo kommen Sie her?
> 
> 
> 

Here, the question word *wo* asks about a static location and the directional aspect is included into the separable verb *herkommen* (*to come here*). So very literally translated it would be: *Where did you come here from?*, not *where are you from?* The literal translation gives a wrong picture though since the usage in English would be quite different.

You could even combine both forms (although that is rare) to generate:

> 
> Woher kommen Sie her?
> 
> 
> 

Usually, marking the directional aspect once is considered enough.

If I had to guess, I would term it a North-South dualism, but I’m not too sure on this.