The function of the subscription frequency and currency selectors is to filter the plans in the pricing dropdown.
The subscription-frequency and currency selectors can be enabled or disabled in Payment Page form settings. The Elementor widget also exposes the corresponding display controls for Elementor-based layouts.
When activated, the selector will appear at the top of the payment form, like this:

The filter applies to all the options based on all plans created, so, when the selectors are deactivated, the plans in the pricing dropdown all display at the same time.
The subscription and currency selectors can be activated separately to limit the plans that appear in the dropdown at a given time.
Currency Symbol vs Unicode Text#
To switch currency display between the symbol and text code, use Currency Options in the form settings. The rendered example above uses the three-letter currency code.