MACRO: Input field?

Is there anyway to get the macros to ask what the modifier should be just like how they have what spell level should be cast at for DND OGL?

Sure!

?{Modifier|0}

gets you a prompt for a value which is initially 0. 

You can also build a dropdown:

?{Modifier|-1|0|+1}

if you want to limit choices.  

You can name those choices like this:

?{Modifier|poor,-1|average,0,|good,+1}

So that a prompt offers a dropdown of poor,average,good. 

Additionally, you can repeat the same label to reuse the value in the formula/macro:

[[1d20-?{Modifier|poor,-1|average,0,|good,+1}]] with a Mod of ?{Modifier}.

Nice thanks.

Any idea why I keep getting a crit error for this?

&{template:atkdmg} {{mod=+5}} {{rname=Longsword}} {{r1=[[1d20+3+2]]}} {{always=1}} {{r2=[[1d20+3+2]]}} {{attack=0}} {{range=5 ft.}} {{damage=[[1d8+3]]}} {{dmg1flag=1}} {{dmg1=[[1d8+3]]}} {{dmg1type=Slashing}} {{damage=1}} {{dmg2flag=1}} {{dmg2=3}} {{dmg2type=Radiant }} {{crit1=$[[20]]}} {{crit2=$[[20]]}} {{save=}} {{saveattr=}} {{savedesc=}} {{savedc=}} {{desc=I glow producing 10 feet of bright light and 10 feet of dim light outside of that, dealing 3 radiant damage to one spell or attack target each turn, and deal 1 radiant damage to all creatures in your bright light (including me) at the end of your turn for 1 minute. }} ammo=ammo {{charname=Sir Dorihiem III}}

I realize I need some sort of inline command but I'm not finding any help on the documents site.  Is it as simple as {{crit1=$[[1d8]]}}?

Rom said:

Is it as simple as {{crit1=$[[1d8]]}}?

Pretty much, but you'll need to remove the $