>I need to write (among others data) from form method with fputs rows in file with latinic and cyrilic letters in same row, for example (utf8 of course)
>
>THIS IS SAMPLE ŠĐČĆĆ ШЂЧЋЖ
>
>I tried but in file occurs ???? for cyrilic letters and some strange letters in output file.
>
>Can you help me with this problem?

For latinic parts,
strconv(strconv("tpšđčć",1),9,1250,1)

for cyrillic parts (assuming they were in codepage 1251),
strconv(strconv("ђшпњ",1),9,1251,1)

You can't have both of 1250 and 1251 in the same field in a table, or same control onscreen. But if these are coming from different sources, this is a way to output them as UTF-8.
Before writing anything into the output file, prefix it with a proper BoM (byte order mark):
FWRITE(nHandle, 0hEFBBBF)