RNFS can't write file as a doc file in iOS

I'm trying to open a doc file written using RNFS. But I'm unable to open that file. When I try to open the file using the word application in iOS , I'm getting this error showing "Can't open file, file format doesn't match the file extension".

`var path = RNFS.DocumentDirectoryPath + "/test.doc";`
`RNFS.writeFile(`
`path,`
`"Project Details\n",`
` "utf8"`
`);`

But this is working fine in android. I'm opening the written file from the file manager itself. But that generated file can be opened using LibreOffice write for mac but, not in iOS. Is there any workaround for this problem.