Buttons group you to group a series of buttons together in a single line through the button group component.

Wrap a series of buttons with .btn in .btn-group.

<div class="btn-group" role="group" aria-label="Basic example">
  <button type="button" class="btn btn-secondary">Left</button>
  <button type="button" class="btn btn-secondary">Middle</button>
  <button type="button" class="btn btn-secondary">Right</button>

Button Group Sizing

.btn-group-lg and .btn-group-sm

<button class="btn-group btn-group-lg" role="group" aria-label="...">...</button>
<button class="btn-group btn-group-sm" role="group" aria-label="...">...</button>