if we travel to the customer's location for repairs, we must also charge for this. unfortunately, the standard module for repairs does not have the option of calculating the travel costs.

if I go through the sale, there is the possibility to calculate shipping costs.  With the help of this app it would be possible to fulfill these requirements. 

https://apps.odoo.com/apps/modules/13.0/shipping_distance_price_knk/

But as I said the deliver button is only shown in the sales module. 

How did odoo imagine the on-site repair? I think that is why the "field service" module was created.  But there I can only charge the time. How would you add or calculate the mileage for a repair?

at the moment I only see the possibility to add a product item with the name "Kilometerpauschale", and to calculate the kilometers manually.

Is it possible to use e.g. the delivery wizards in the sales module in the same way in the field service module or repair module?