Encryption is a means of protecting your data from unauthorized users. Think of it as putting all your data into a box, locking it and sending it to the recipient who is the only other person with the key. If anyone else between you and the recipient were to try and tamper with the box, they wouldn't be able to see the contents as it is locked. And unlike a physical box that can be broken, digital encryption is built with mathematics meaning that in order to break it, the most powerful computer in the world would need to try for thousands of years before it can randomly stumble on the key.
Windscribe uses the highest grade encryption to secure your data when you enable the VPN, and this is on top of the existing encryption that most websites already use by default so when using the VPN, it's more like a locked box inside another locked box. And if something doesn't already use the encryption, well then Windscribe's locked box will definitely help keep prying eyes off your data.