How to remove woocommerce checkout fields?

Ans :  
In WooCommerce there is no built-in function to remove checkout fields and billing details heading from checkout page. So we remove these fields pragmatically using hooks supplied by Woocommerce.

What you need to do is open your child theme's functions.php file and write the following code.

functions.php

// Removing checkout fields
add_filter( 'woocommerce_checkout_fields' , 'wc_remove_checkout_fields' );

function wc_remove_checkout_fields( $fields ) {
    unset($fields['billing']['billing_first_name']);
    unset($fields['billing']['billing_last_name']);
    unset($fields['billing']['billing_company']);
    unset($fields['billing']['billing_address_1']);
    unset($fields['billing']['billing_address_2']);
    unset($fields['billing']['billing_city']);
    unset($fields['billing']['billing_postcode']);
    unset($fields['billing']['billing_country']);
    unset($fields['billing']['billing_state']);
    unset($fields['billing']['billing_phone']);
    unset($fields['order']['order_comments']);
    unset($fields['billing']['billing_address_2']);
    unset($fields['billing']['billing_postcode']);
    unset($fields['billing']['billing_company']);
    unset($fields['billing']['billing_email']);
    unset($fields['billing']['billing_city']);
    return $fields;
}

// Removing billing details heading and additional information text
add_filter( 'gettext', 'wc_billing_field_heading', 20, 3 );
function wc_billing_field_heading( $translated_text, $text, $domain ) {
    switch ( $translated_text ) {
        case 'Billing details' :
            $translated_text = __( '', 'woocommerce' );
            break;
        case 'Additional information' :
            $translated_text = __( '', 'woocommerce' );
            break;
    }
    return $translated_text;
}


The above code will remove all billing fields and billing field heading. Change the code according to your choice.