Cacher is the code snippet organizer for pro developers

At Appearance > Widgets, drag a Genesis – eNews Extended widget into the Horizontal Opt-in widget area and configure it.

If you are using MailChimp, you would need to enter the URL from the form embed code in the Form Action
field. See this page for details.

This is a newer and updated version of the earlier tutorial on registering a custom widget area and displaying eNews Extended plugin’s widget in it below the site header.

We shall use Flexbox to align the widget title and input fields horizontally.

Install and activate Genesis eNews Extended plugin.

/* Horizontal Opt-in
-------------------------------------------- */

.horizontal-opt-in {
	background-color: #50c5b5;
	color: #fff;
	padding: 20px;
}

.horizontal-opt-in .enews {
	display: -webkit-box;
	display: -webkit-flex;
	display: -ms-flexbox;
	display: flex;
	-webkit-box-pack: center;
	-webkit-justify-content: center;
	    -ms-flex-pack: center;
	        justify-content: center;
	-webkit-box-align: center;
	-webkit-align-items: center;
	    -ms-flex-align: center;
	        align-items: center;
	max-width: 1000px;
	margin: 0 auto;
}

.horizontal-opt-in .widget-title {
	margin-bottom: 0;
	font-size: 20px;
	margin-right: 20px;
}

.horizontal-opt-in form {
	display: -webkit-box;
	display: -webkit-flex;
	display: -ms-flexbox;
	display: flex;
	-webkit-box-flex: 1;
	-webkit-flex: 1;
	    -ms-flex: 1;
	        flex: 1; /* grow this item to fill the available space */
}

.horizontal-opt-in .enews-widget input {
	margin-bottom: 0;
	width: auto;
	margin-right: 10px;
	padding: 10px;
	line-height: 1;
	font-size: 15px;
	border: none;
	-webkit-box-flex: 3;
	-webkit-flex: 3;
	    -ms-flex: 3;
	        flex: 3;
}

.horizontal-opt-in .enews-widget input[type="submit"] {
	margin-right: 0;
	padding: 10px 50px;
	background-color: transparent;
	border: 2px solid #fff;
	-webkit-box-flex: 1;
	-webkit-flex: 1;
	    -ms-flex: 1;
	        flex: 1;
}

.horizontal-opt-in .enews-widget input[type="submit"]:hover {
	background-color: #fff;
	color: #333;
}

@media only screen and (max-width: 860px) {

	.horizontal-opt-in .enews {
		-webkit-box-orient: vertical;
		-webkit-box-direction: normal;
		-webkit-flex-direction: column;
		    -ms-flex-direction: column;
		        flex-direction: column;
	}

	.horizontal-opt-in .widget-title {
		margin-bottom: 20px;
	}

	.horizontal-opt-in form {
		width: 100%;
	}

}

@media only screen and (max-width: 620px) {

	.horizontal-opt-in form {
		-webkit-box-orient: vertical;
		-webkit-box-direction: normal;
		-webkit-flex-direction: column;
		    -ms-flex-direction: column;
		        flex-direction: column;
		width: 100%;
	}

	.horizontal-opt-in .enews-widget input {
		margin-right: 0;
		margin-bottom: 20px;
	}

	.horizontal-opt-in .enews-widget input:last-child {
		margin-bottom: 10px;
	}

}

// Register Horizontal Opt-in widget area
genesis_register_widget_area(
	array(
		'id'          => 'horizontal-opt-in',
		'name'        => __( 'Horizontal Opt-in', 'my-theme-text-domain' ),
		'description' => __( 'This is the horizontal opt-in section.', 'my-theme-text-domain' ),
	)
);

// Display Horizontal Opt-in widget area below header
add_action( 'genesis_after_header', 'sk_horizontal_optin' );
function sk_horizontal_optin() {
	genesis_widget_area( 'horizontal-opt-in', array(
		'before'	=> '<div class="horizontal-opt-in widget-area"><div class="wrap">',
		'after'		=> '</div></div>',
	) );
}

https://sridharkatakam.com/horizontal-opt-form-genesis-using-enews-extended-plugin-flexbox/