Elevator pitch, also known as elevator speech or a statement, is a description of a business idea for a product/service delivered in front of a prominent figure (angel investor, vc capital, board member...) within a limited timeframe. The term highlights the fact that decision-making figures have rather busy schedules and that the idea can be presented during short, limited breaks such as an elevator ride.
What sets an elevator pitch apart from a regular pitch is the fact that the elevator pitch is concise, short, simple, to the point, written in such a way that everyone can understand what your product/services solves and is delivered in 30-60 seconds.
The key question your elevator pitch needs to answer is what your company does. Many investors, after hearing a pitch, still have no idea what it is that you do. So, keep it short and simple by using one of the many positioning statements. (e.g. [proven industry name] for/of [your niche])
Also, avoid using jargon and overcomplicate things. Focus on what is important and keep practising delivering it. Good luck!