Transfer agreement

I do not know if it is a right section to talk about the contract of sale, but I have some doubts and would like to make a couple of questions and thank you to those who answer me.
Since you're more experienced than me, here they are:

- The private sector has the opportunity to sell puppies with a contract of sale?
- Or is it necessary to ask some permission to do so?

I'm not 100% sure what you are asking...

Do you mean is it normal to sign a contract when buying your kittens? Or do you want to know if you need to sign a contract or get permission to breed them?