Bootstrap class: .form using the grid

<form>
  <div class="form-group row">
    <label for="inputEmail3" class="col-sm-2 col-form-label">Email</label>
    <div class="col-sm-10">
      <input type="email" class="form-control" id="inputEmail3" placeholder="Email">
    </div>
  </div>
  <div class="form-group row">
    <div class="col-sm-10 offset-sm-2">
      <button type="submit" class="btn btn-primary">Sign in</button>
    </div>
  </div>
</form>

Preview

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