What is better a copyright or a trademark?

Your question is not very clear in what you want to copyright/trademark.

Copyright is automatic and is used mostly in relation to written works, e.g. song lyrics, news articles, novels to name a few.

If it is a trade name you wish to protect, then copyright will not necessarily protect this alone. If you produce leaflets/flyers or other any brochure type material, then it will be protected.

If you wish to protect a trading name and/or logo, then this must be registered with the Intellectual Property Office (formerly, the Patent Office).

Fees for doing this are in the region of £250 and are subject to re-registration every few years to keep the registration active.

Type Intellectual Property Office into your search engine and follow the on screen leads to Trade Marks and this, hopefully will answer all the questions you have on the subject.

May I wish you good luck with your venture.

A copyright is for a written product, such as a book or article. A trademark is for the name, such as Mattel. You often a littel TM next to it. For a product, like an electrical device, you want a patent to prove its your original idea.