<input type="file" id="upload" hidden/>
<label for="upload">Choose file</label>

label{
  display: inline-block;
  background-color: indigo;
  color: white;
  padding: 0.5rem;
  font-family: sans-serif;
  border-radius: 0.3rem;
  cursor: pointer;
  margin-top: 1rem;
}