Remove quantity field when a product can only be sold individually WooCommerce https://wpsites.net/wordpress-tutorials/remove-quantity-field-when-a-product-can-only-be-sold-individually-woocommerce/

functions.php

function remove_quantity_field_for_sold_individually_products() {
    if ( is_product() ) {
        global $product;

        if ( is_object( $product ) && $product->is_sold_individually() ) {
            // Remove the quantity field
            remove_action( 'woocommerce_before_add_to_cart_quantity', 'woocommerce_template_single_add_to_cart', 10 );
            remove_action( 'woocommerce_after_add_to_cart_quantity', 'woocommerce_template_single_add_to_cart', 10 );
        }
    }
}
add_action( 'wp', 'remove_quantity_field_for_sold_individually_products' );