How to write a file to a folder located at Apple’s Files App in Swift

You can use UIDocumentInteractionController and let the user select where he wants to save your file when you share your url. The user just needs to select save to files and choose which directory to save the file you are exporting.

You can use UIDocumentInteractionController to share any file type located inside your App bundle, at your Documents directory or another folder accessible from your App.

class ViewController: UIViewController {
    let documentInteractionController = UIDocumentInteractionController()
    func share(url: URL) {
        documentInteractionController.url = url
        documentInteractionController.uti = url.typeIdentifier ?? "public.data, public.content"
        documentInteractionController.name = url.localizedName ?? url.lastPathComponent
        documentInteractionController.presentOptionsMenu(from: view.frame, in: view, animated: true)
    }
    @IBAction func shareAction(_ sender: UIButton) {
        guard let url = URL(string: "https://www.ibm.com/support/knowledgecenter/SVU13_7.2.1/com.ibm.ismsaas.doc/reference/AssetsImportCompleteSample.csv?view=kc") else { return }
        URLSession.shared.dataTask(with: url) { data, response, error in
            guard let data = data, error == nil else { return }
            let tmpURL = FileManager.default.temporaryDirectory
                .appendingPathComponent(response?.suggestedFilename ?? "fileName.csv")
            do {
                try data.write(to: tmpURL)
                DispatchQueue.main.async {
                    self.share(url: tmpURL)
                }
            } catch { 
                print(error)
            }

        }.resume()
    }
}

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extension URL {
    var typeIdentifier: String? {
        return (try? resourceValues(forKeys: [.typeIdentifierKey]))?.typeIdentifier
    }
    var localizedName: String? {
        return (try? resourceValues(forKeys: [.localizedNameKey]))?.localizedName
    }
}

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edit/update:

If you would like to expose the files located on your App Bundle’s document directory you can check this post How can I display my App documents in the Files app for iPhone