The function of the subscription frequency and currency selectors is to filter the plans in the pricing dropdown.
The subscription and currency selectors can be easily activated or deactivated in the Elementor widget settings.
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, limiting the plans that appear in the dropdown at a given time, and giving you complete flexibility and control over how to display the plans.