To add space between columns in Bootstrap use gutter classes. With gutters you can add horizontal or vertical space or even specify how big space should be on different screen size.

• Gutters are the gaps between column content, created by horizontal padding. We set padding-right and padding-left on each column, and use negative margin to offset that at the start and end of each row to align content.
• Gutters start at 1.5rem (24px) wide. This allows us to match our grid to the padding and margin spacers scale.
• Gutters can be responsively adjusted. Use breakpoint-specific gutter classes to modify horizontal gutters, vertical gutters, and all gutters.

.gx-* classes can be used to control the horizontal gutter widths. The .container or .container-fluid parent may need to be adjusted if larger gutters are used too to avoid unwanted overflow, using a matching padding utility.

<div class="container px-4">
  <div class="row gx-5">
    <div class="col">
      <div class="p-3">Custom column padding</div>
    </div>
    <div class="col">
      <div class="p-3">Custom column padding</div>
    </div>
  </div>
</div>