Conversion rate refers to the number of people who got converted as your customers divided by the number of customers who actually visited your website. For example, if there are 200 visitors on your website every day but only 50 sales then the conversion rate is 25%. 

Conversion rate is the desired action that you want a user to take. It might be a sign-up, taking a demo, etc. Different websites and businesses have different goals and objectives and thus the conversion rate is different for each of them. Tracking conversion rates allows you to measure the performance of your web pages and apps. Understanding what percentage of your users are completing the goals that drive your business allows you to gauge the success of your site or app and identify areas for improvement.