Under what license should the product be released?

Question

Copyright

Suppose there is a small group of developers who write custom software (add-ons / extensions for CMS, individual scripts, etc.)
Under what public license (ready-made text) can the result of the work be given to the customer so that he can use all the sources at his discretion ? Those. had the opportunity to change the product, set their own copyrights, sell under their own license, etc.?

Answer 1

The BSD licene and Apache license are compatible with your requirements with certain reservations.
You can also release the code in the public domain, i.e. do not impose any license on it, give it to the public domain, then it will fully meet your requirements (it is enough to indicate in the code that it is provided in the public domain).
But you need to be careful if you use third-party code, for example, any libraries or other borrowings from someone else's code. In this case, you must not violate the licenses associated with the borrowed code.
(crossed out)
sorry, misread the question.
You just need to transfer the code to the customer under the terms of the contract, indicate in the contract that the customer has full exclusive rights to this code.

Answer 2

Freelancers? Company?
It seems that this is not about opening the code under an open license, since the customer must make his own decision about this.
If we are talking about a license agreement, then why not seek the help of a lawyer? Why guess on coffee grounds?
In the simplest case, the contract might look like this:
forcelawyer.com/documenrt/dogovor/dogovory-postavk...