title: How to upload .pdf, .docx, .xls in Ionic
body: <p>Ionic File Transfer option showing image upload but there is no option showing file type of doc, pdf, csv.</p>
  
  <pre><code>let options: FileUploadOptions = {
       fileKey: 'file',
       fileName: 'name.jpg',
       headers: {}
       .....
    }
  </code></pre>
  
  <p>Explain to me the option.</p>