Your content is automatically copyrighted
When you write your own text or take your own pictures they are automatically covered by Copyright. It's free and happens automatically in the UK and US.
That means that nobody can use your content without permission.
If you find anybody using your website content you could take legal action.
If you use copyrighted content
Once you understand the above, you will understand why you cannot copy someone else's text for your own website content.
When you write the text for your website, it needs to be 100% original and fresh.
You can of course take inspiration from a competitor's work, but you need to write the actual words from scratch.
Being caught is as simple as someone copying that text into Google, searching, and your website will come up.
If caught you are subject to hefty fines.
For more info on what to write and how to send your content, see here: Sending Content.
This applies to images too
Do NOT save images from Google.
This is the most common way people get caught out with copyright claims.
Do not save from Wikipedia. Do not save from your competitor's websites. Do not save images from ANYWHERE other than specific royalty-free image libraries designed for this purpose. For more info on finding images you can see, see here: Sending your Logo, Images & Video.