What is declaration incorrectly

C and C++ are case sensitive: Void is not the same a void.

Void f(void);

The same thing applies to Int and all other keywords, functions, properties, and so forth.
It also requires the header file names to be accurate:

#include <studio.h>

Should be

#include <stdio.h>

It's a very good idea to also do three other things with your code:
1) Indent it!
This is hard to read at best:

include <studio.h>
Void f(void);
Int main(void)
{
Int i;
for (i=0;  i<10; i++) f( );
return 0;
}
Void f(void)
{
int j=10;
printf("%d " , j)
j++;
/* This line has no lasting effect*/
}

Indent it, and it's more obvious:

include <studio.h>
Void f(void);
Int main(void)
    {
    Int i;
    for (i=0;  i<10; i++) f( );
    return 0;
    }
Void f(void)
    {
    int j=10;
    printf("%d " , j)
    j++;
    /* This line has no lasting effect*/
    }

2) Particularly when you are getting started, always use curly brackets even when tehy aren't strictly needed.

int main(void)
    {
    int i;
    for (i = 0; i < 10; i++) 
        {
        f( );
        }
    return 0;
    }

That way, when you change your code, you are a lot, lot more likely to get the new lines of code inside your loop instead of after it!

3) Don't use single character names: they may be easier to type, but they are also a lot easier to get wrong, and much harder to work out what is going on. And when you come back to code after a month on something else, readability is very, very important! Having meaningful names for variables and functions helps your code be self documenting, and that makes it a lot easier to work with.

#include <studio.h>
Void f(void);
Int main(void)
{
Int i;
for (i=0;  i<10; i++)
 f( );
return 0;
}
Void f(void)
{
int j=10; /* Note that this line resets j every time you call s, this is local variable*/
printf("%d " , j);
j++; /* 1) This line has no lasting effect*/
/* 2) because effect start to apply here*/
} /* 3) and ends here*/

Try

#include <studio.h>
Void f(void);
Int main(void)
{
Int i;
for (i=0;  i<10; i++) f( );
return 0;
}
Void f(void)
{
int j=10;
j++; /* Move the line here to see its effect on print */
printf("%d " , j);
}

You may want to study variables scope.