ADR stands for additional dialogue recording and it's not really something that screenwriters need to be concerned with. There are several ways to do a voiceover, and it's more for us to write the story in the clearest way possible.

The "muffled" rendition is probably the best option since it's viewed from outside but we still hear what's going on inside. V.O. isn't right since that's used when the speaking character is either in the shot, but thinking, or not in the scene at all. O.S. stands for off-stage or off-screen, and is used when the character is in the scene, but not on camera (i.e. you're wanting to focus on something else). You have a character that is on camera, in the scene, and vocally speaking, which means you shouldn't use either one, hence, the wryly being the best choice.

You are going to need a poll thing pretty soon.

I think it's a voice over because your character inside the store is not on a microphone.  Your scene is outside the store and what you're going to hear live is street noise, the guy pacing, etc..  Any dialogue from the character inside is going to be added after the fact.

It's tricky and a little arty and you just have to script it so it's easy to follow.  You also have to keep focus on the character outside.  Everything you describe including the gal's lines have to come from his POV.

EXT. PAWNSHOP - DAY

On the sidewalk outside a pawnshop, X watches Y though the barred window glass present her guitar case to a guy behind the store counter.  X loses sight of Y's face as she turns her back on him but when she begins to gesture with her hands he knows the negotiation has begun.  

Y (V.O.)
Dialogue

You could look at Martin's "Anniversary" for a general idea as well.

Thanks everyone.  This is all good to know.  I should mention that this is an animation script so I guess the street noise, location of mic, etc. wouldn't be an issue here for the director but it's still good to know for future reference.

To be honest I think I can get away with V.O.   As I read it, it seems pretty clear to me what I'm trying to get across, however the muffled option does seem more technically accurate.  It's a toss-up at the moment.

I checked out 'Anniversary'.  The V.O. optioned worked well for this particular story since it was a true narration, however mine's not.

Hello, if anyone is about I could do with some help on this please.

The script I am working on at the moment is narrated by the central character of the script (in fact the only speaking character of the script). For the purposes of this question I will call him 'Jon'. Jon's first piece of narration is before I introduce him as a character, his first narration is over a scene of his workplace but he does not appear in it. At the moment I have.. (example, not the real script.)

Quoted Text EXT. OUTSKIRTS OF TOWN - NIGHT The factory stands on a hill overlooking the town.                Mans voice (V.O.)     It was one of those days in the factory. INT. FACTORY JON (40's) is standing in the corner reading a magazine.                 JON (V.O.)      I was working the night shift......

Instead of Mans voice (V.O.) can just write JON (V.O.) ?

Or is there anything else i should do?

Cheers

Just use Jon (V.O.).

Think of it from a production standpoint.  It just adds an unnecessary level of difficulty for the people shooting the script if they have to go in and write JON in ink off to the side so they can keep track of who is speaking.

Thanks Tierney_cat, much appreciated.

Cheers