Edit in JSFiddle

const fileInput = document.getElementById('file');
fileInput.onchange = () => {
  const selectedFile = fileInput.files[0];
  console.log(selectedFile);
  document.getElementById('inputBox').value =selectedFile.name;
}

<br/><br/>
<div class="col-lg-6 col-sm-6 col-12">
  
            <div class="input-group">
                <label class="input-group-btn">
                    <span class="btn btn-primary">
                        Browse&hellip; <input type="file" style="display: none;" id="file" multiple>
                    </span>
                </label>
                <input type="text" class="form-control" id="inputBox" readonly>
            </div>
           
        </div>