Switch

Label beside — the settings-row seat:

Label above — the field-row seat:

The toggle editor: a switch, and the Toggle family's default method. Reads as a setting that takes effect — the affordance says this is on now, not this will be on when you submit.

Reach for it when

Enabling a feature, choosing a mode, turning a display option on: show_map, members_only, accepting_bookings. The label names the thing being enabled, and "off" is simply its absence — a switch has one label and an implied opposite.

Declaring one

When another method fits better

• Both states need a word — radio.
• It reads as agreeing or including rather than enabling — checkbox.