How to set up "your" delivery in Satchmo (Django)?

Question

Django

Hey!
If anyone has used a Django-based CMS for stores, they may have had to customize the shipping method to suit their needs, because it comes with all sorts of FedEx, Canadian Express, and more.
Interested in the possibility of setting up delivery of local importance, such as all sorts of private companies, etc. I am also interested in the possibility of setting up an option in Payment - payment on arrival, that is, payment takes place directly at the place of delivery and does not interact with the site in any way.
How to do it? Of.documentation does not particularly talk about this.