Put !DIR$ followed by a space anywhere in the line.
The !DIR$ characters are the first nonblank characters in the line (actually, non-whitespace).
Directives are listed after the space.
An initial directive line has a blank, tab, or newline in the position immediately after the !DIR$.
A continuation directive line has a character other than a blank, tab, or newline in the position immediately after the !DIR$.
Thus, !DIR$ in columns 1 through 5 works for both free-form source and fixed-form source.