how to change button background color in bootstrap 4 code example

Example 1: custom color bootstrap buttonm

.btn-primary, .btn-primary:hover, .btn-primary:active, .btn-primary:visited {
    background-color: #8064A2 !important;
}

Example 2: how to change the color of a bootstrap button

.btn-default
 
{
 
background-color: #68889E;
 
color:#FFF;
 
border-color: #2F3E48;
 
}
 
.btn-default:hover, .btn-default:focus, .btn-default:active, .btn-default.active, .open .dropdown-toggle.btn-default {
 
 
 
background-color: #2F3E48;
 
color:#FFF;
 
border-color: #31347B;
 
}

Example 3: button color bootstrap

<div class="btn-group btn-group-toggle" data-toggle="buttons">
  <label class="btn btn-secondary active">
    <input type="radio" name="options" id="option1" autocomplete="off" checked> Active
  </label>
  <label class="btn btn-secondary">
    <input type="radio" name="options" id="option2" autocomplete="off"> Radio
  </label>
  <label class="btn btn-secondary">
    <input type="radio" name="options" id="option3" autocomplete="off"> Radio
  </label>
</div>