Checkbox

Checkbox toggles a single independent boolean ("Remember me", "I agree") or selects several items from a list where choices aren't mutually exclusive. It supports an indeterminate state for a parent that summarizes a partially-selected group. Reach for RadioGroup instead when exactly one of a few options must be chosen, or Switch when the change applies immediately with no Save step.

Pair every checkbox with a Label. The box alone is a tiny hit target with no accessible name; an associated Label both names it and extends the click area to the text. Keep the wording affirmative so checking it means "yes" — "Send me updates", not "Don't send updates".

Use indeterminate only for a summary parent. It's the visual for "some but not all children selected" in a select-all pattern — never a third user-settable value. Drive it from the children's state; clicking it should resolve to all-on or all-off.

Don't make a checkbox apply instantly. Checkboxes imply a pending choice confirmed on submit; if the toggle takes effect the moment it changes (a setting), that's a Switch. Group related checkboxes under a shared heading or fieldset so the relationship is announced.