When you use any Online services, you trust them with your information. The website or login you visit, collect certain type of information, most commonly the information you share by yourself. Such as Username, Password and other login information that you type at any login page.
Along with the information which is share to that visited website by yourself, there is some information share without asking your permission, or even sometimes without informing you. That information is most likely shared by the web browser you are using, like Google Chrome, Mozilla Firefox MS Edge etc.
There could be numerous type of information which is automatically shared such as the time and the date you visited that webpage, name and the version of web browser you are using, screen resolution and size of your device, your IP address etc.
How to Know Which Website is Sharing What?
As we already have mentioned, that some of the information is bound to be share when you visit any website or login page of that website, by what you provide and automatically. However, some website demand or need more information than what you expect. Such as Social Media Giant Facebook, or Google, YouTube and other Web Giants who require more information in order to make their service better and better.