Add New Tab to the WooCommerce My Account Page

functions.php

/**
 * @snippet       Add New Tab to WooCommerce My Account Page
 * @author        Hire Jordan Smith // https://hirejordansmith.com
 */

// Register new endpoint to use for My Account page
add_action( 'init', 'hjs_add_account_update_endpoint' );
function hjs_add_account_update_endpoint() {
    add_rewrite_endpoint( 'account-update', EP_ROOT | EP_PAGES );
}

// Add new query var
add_filter( 'query_vars', 'hjs_account_update_query_vars', 0 );
function hjs_account_update_query_vars( $vars ) {
    $vars[] = 'account-update';
    return $vars;
}

// Insert the new endpoint into the My Account menu
add_filter( 'woocommerce_account_menu_items', 'hjs_add_account_update_link_my_account' );
function hjs_add_account_update_link_my_account( $items ) {
    $items['account-update'] = 'Account Details';
    return $items;
}

// Add content to the new endpoint
add_action( 'woocommerce_account_account-update_endpoint', 'hjs_account_update_content' );
function hjs_account_update_content() {
    echo '<h3>Account Details</h3>';
    echo do_shortcode('[gravityform id="3" title="false" description="false" ajax="true" tabindex="-1"]');
}