It's important that users understand how to use interactive elements such as <input>. In many cases, a description is useful and so you may have some visible element on the screen, for example Fields have help text that can be displayed in a variety of ways.
To make these descriptions accessible to users of assistive techologies you can use the aria-describedby attribute to indicate the text that describes an interactive element. Field Controls automatically use aria-describedby if help text is provided.
For example:
<label for="emailField">Email</label>
<input id="emailField" aria-describedby="emailHelp" type="email">
<span id="emailHelp">This field should contain an email address</span>
For an interactive feature that would benefit from having a description for users of assistive techologies, you can use a control's ARIA Described by property to choose the Id of another Text Control or Hyperlink Control on the page.