WordPress at a glance
function is not described

WC_Order::set_billing_email() public WC 1.0

Set billing email.

{} It's a method of the class: WC_Order{}

No Hooks.

Return

Null. Nothing.

Usage

$WC_Order = new WC_Order();
$WC_Order->set_billing_email( $value );
$value(string) (required)
Billing email.

Code of WC_Order::set_billing_email() WC 5.0.0

<?php
public function set_billing_email( $value ) {
	if ( $value && ! is_email( $value ) ) {
		$this->error( 'order_invalid_billing_email', __( 'Invalid billing email address', 'woocommerce' ) );
	}
	$this->set_address_prop( 'email', 'billing', sanitize_email( $value ) );
}