Can you copyright a business name and website

I am planning to open a business and create a website can I copyright my brand name and the website so my posts can't be copied without my permission? If so how do you do this

You would protect your brand name by getting a trade mark. See https://www.gov.uk/topic/intellectual-property/trade-marks

Your web site is copyright as soon as you create it. It might help (but is not required) to put a copyright symbol (a 'c' enclosed in a circle -- i.e. © ) on it.