How to create and save file to Files application (iOS platform)

I need to create PDF-file (done) and save it to Files application, so user can access it anytime outside of my app. I tried rn-fetch-blob and react-native-fs packages and they worked fine for Android, but for iOS they can only create files to internal app storage (so files are not created in external storage, i.e. not in iOS Files application). What options do I have to save my created files to Files application? I know that it is possible, i.g. Slack app allows saving files to Files app.