input type file w3schools code example

Example 1: upload button in html

<form action="/action_page.php">
  <input type="file" id="myFile" 
  name="filename">
  <input type="submit">
</form>

Example 2: specifying file types in html file input

<input id="fileSelect" type="file" accept=".csv, application/vnd.openxmlformats-officedocument.spreadsheetml.sheet, application/vnd.ms-excel" />