lunate What he said. Usually an Editor will send you a contract to your e-mail. If you haven't received that, you can use a form. There is a form to submit your novel, and they will consider whether to give you contract or not.
https://docs.google.com/forms/d/e/1FAIpQLSchNZTTmOK7vz3cOrrtcm0rFKXT6PIgIZ-7CaT6ZonB_leg3w/viewform
This is the form, and you can have a look. As for whether it's worth it or not. I already mentioned somewhere else, that it depends on the individual. Some will find it not acceptable, other might accept it without further thoughts. Whether you should take this or not, should be your choice. The best advice anyone can give you, is to read the contract (when you have it). If you don't understand something, a lawyer is the best option. It's never a good idea signing something you don't understand, right?