bootstrap/site/content/docs/4.6/utilities/screen-readers.md

layout	title	description	group
docs	Screen readers	Use screen reader utilities to hide elements on all devices except screen readers.	utilities

Hide an element to all devices except screen readers with .sr-only. Combine .sr-only with .sr-only-focusable to show the element again when it's focused (e.g. by a keyboard-only user). Can also be used as mixins.

{{< example >}} Skip to main content {{< /example >}}

// Usage as a mixin
.skip-navigation {
  @include sr-only;
  @include sr-only-focusable;
}