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 online) 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 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). Depending on whether one or both parties are sharing confidential information, you can make either a mutual Non-disclosure agreement or One-way confidentiality agreement.
Make sure your agreements with independent consultants have the necessary provisions relating to IP created in the course of working for you. Rocket Lawyer’s Consultancy agreement sets out that any IP created by a consultant is owned by the client who engaged the consultant.
If a party breaches your copyright, consider sending a Cease and desist letter for IP infringement or otherwise coming to an agreement to protect your intellectual property. For more information, read Remedies for intellectual property right infringement.