In such a case one would create a FDF document (fdf_create()) set the values of each input field (fdf_set_value()) and associate it with a PDF form (fdf_set_file()).
참고: If you run into problems configuring php with fdftk support, check whether the header file FdfTk.h and the library libFdfTk.so are at the right place. They should be in fdftk-dir/include and fdftk-dir/lib. This will not be the case if you just unpack the FdfTk distribution.