in html

                <input type='file' id="file" name='file' class="form-control">

                <input type="button" id="submit" value='Submit' class='btn btn-success'>

in script

$('#submit').click(function(){
  var files = $('#file')[0].files;

  if(files.length > 0){
                     var fd = new FormData();

                     // Append data 
                     fd.append('file',files[0]);
                     fd.append('_token',CSRF_TOKEN);

                     // Hide alert 
                     $('#responseMsg').hide();

                     // AJAX request 
                     $.ajax({
                          url: "",
                          method: 'post',
                          data: fd,
                          contentType: false,
                          processData: false,
                          dataType: 'json',
                          success: function(response){


                          },
                          error: function(response){

                          }
                        });     

   }                        


});

OR

<form action="" method="POST" id="file-upload" enctype="multipart/form-data">
               
        
                <div class="mb-3">
                    <label class="form-label" for="inputFile">Select File:</label>
                    <input 
                        type="file" 
                        name="file" 
                        id="inputFile"
                        class="form-control">
                    <span class="text-danger" id="file-input-error"></span>
                </div>
         
                <div class="mb-3">
                    <button type="submit" class="btn btn-success">Upload</button>
                </div>
            
            </form>

<script type="text/javascript">

    $.ajaxSetup({
        headers: {
            'X-CSRF-TOKEN': $('meta[name="csrf-token"]').attr('content')
        }
    });
  
    $('#file-upload').submit(function(e) {
        e.preventDefault();
        let formData = new FormData(this);
        $('#file-input-error').text('');

        $.ajax({
            type:'POST',
            url: "",
            data: formData,
            contentType: false,
            processData: false,
            success: (response) => {
                if (response) {
                    this.reset();
                    alert('File has been uploaded successfully');
                }
            },
            error: function(response){
                $('#file-input-error').text(response.responseJSON.message);
            }
       });
    });
      
</script>