Copyright is applied to all original works automatically, so you don't even need to mark it on your work.
Whilst there is no official registration, you should take steps to protect your copyright by providing evidence that you had the work at a particular time, for example by depositing a copy with a bank or a solicitor.
A number of private companies operate unofficial registers, but check exactly what you are getting for your money before going down this route.
When you publish copyright material (either in paper form or on-line) mark it with the international copyright symbol © followed by the name of the copyright owner and the year of creation. This is the language you will always see on the front pages of a copyright book.
When you share your valuable confidential information, including copyright, with another business, you can consider using an appropriate confidentiality agreement (also known as a non-disclosure agreement or NDA). You can use Rocket Lawyer’s simple interview process to create either a mutual Non-disclosure agreement or One-way confidentiality agreement, depending on whether one or both parties are sharing confidential information.
Make sure your agreements with independent consultants have the necessary provisions relating to IP created in the course of working for you.
If a party breaches your copyright, consider issuing a Cease and desist letter to protect your intellectual property.