Unable to find the directory created with Capacitor Filesystem API on my device

Ionic Framework ionic-v3
1

Hello,
I want to Create Directory using the Capacitor FileSystem api. Earlier using cordova File plugin i was able to create the directory on my mobile device with this code and i was able to see the folder in my file manager.

    this.file.createDir(this.file.externalRootDirectory, 'TestFolder', true).then(() => {
      alert('Directory Created Successfully');
    }, (err) => {
      alert('Error While Creating Directory');
    });

Now in capacitor i am trying to create a folder like this

  async WriteFileInExternalStorage() {
    try {
      let ret = await Plugins.Filesystem.writeFile({
        path: 'TestFile.txt',
        data: "This is a test",
        directory: FilesystemDirectory.ExternalStorage,
        encoding: FilesystemEncoding.UTF8
      });
      alert('Directory Created Successfully');
    } catch (e) {
      alert('Error While Creating Directory');
    }
  }

Even though it showing Directory has been created successfully, but i am unable to see the folder in my device(I don’t have SD card in my device,i want to save it to the internal storage)
Can somebody please help me to create a directory in my device using capacitors filesystem api so that i can see the folder in my device file manager.