Shipping cost depends on the length of the package

Hi,

In shipping methods, you can use the minimum volume and maximum volume options to restrict the shipping method based on the total volume of the products in the cart.
If you want instead to restrict the shipping method based on the total length of the products, you should cheat by setting the width and height of all the products to 1 since the volume is length*width*height.
But maybe I didn't understand enough of your problematic to make this a viable solution.

Otherwise if you want to add extra shipping fees for some products, that's totally possible. Enable the "shipping price per product" setting in your shipping method. Then, when you edit a product in the backend, you'll get a "shipping prices" area where you can add extra fees for that product for each shipping method with that setting turned on.

Hi,

will the shipping type set in this way be displayed for the product in which it is set, or also for other products.

I'm not sure I understand your question.
If you use shipping prices per product, then for example: suppose you set a shipping price of 5€ for product A and 0€ for product B.
If product A is in the cart, the shipping fee will be 5€
If product B is in the cart, then shipping fee will be 0€
And if both product A and product B are in the cart, the shipping fee will be 5€
If product C has a shipping fee of 10€ and both A and B are in the cart, the shipping fee will be 15€

How to configure so that this shipping method is displayed only for a given product - do you need to introduce any restrictions to filter it appropriately?

If you want to block a shipping method to appear when some specific products are in the cart, you can use the "block" checkbox of the shipping method in the "shipping prices" area of each product (once the "shipping price per product" setting is activated:
www.hikashop.com/support/documentation/3...ng-manual-price.html