An e-bike is a bike that provides additional electrical assistance when pedalling. The motor and battery ensure that this assistance is generated and transmitted. This makes riding an e-bike not only faster, but also more comfortable. You have to exert less effort when pedalling than with a normal bike.
The use of these terms can lead to confusion. In fact, the terms electric bike and e-bike are used synonymously by everyone. There are also different spellings: ebike, e bike and e-bike. The word e-bikes is simply another name for electric bikes, but it seems more modern and is a bit more daring.. Don't worry about the different terms: Everyone understands what you are talking about when you refer to an e-bike or electric bike.