Your question isn't really clear so I'll see if the following helps:
Am back with my question,
The Default letter spacing between two characters in Indesign is 1/1000 of em, This is called a unit value.
In the same way What is the Unit value in 3b2 for signle letter space?. (Ie the Letter spacing between two characters)
Hi Dilip. It can be whatever you want it to be. The default value, I think, is zero. You can check what value is applicable using the Property Inspector tool. I can't take a screenshot right now but it is normally in the lower-right toolbar area.