I assume that you're visiting your email provider's website (using Chrome), rather than using a dedicated email client (such as Windows 10 Mail). If so, what you see on your screen will depend upon which email provider you use. (For example, people who use Outlook.com won't see the same thing as those who use Gmail which, in turn, will look different to what users of Yahoo or GMX will see).
So it's hard for us to give a precise answer to your question (because we can't see what's on your screen). However the following general information might well help:
1. If you've already opened an email there should be a 'delete' button available for you to click on ;
2. If you're looking at a list of email there's probably a little square box alongside each one. Clicking on a box 'selects' that email. You can click on lots of boxes to select a batch of emails or, quite often, you can select a block of emails simply by clicking on the first one and then holding down 'Shift' while selecting on the end one. Once you selected some emails there's likely to be a pull-down menu at the top of the list, where you can choose between options such as 'Mark as Read' or 'Delete'.
3. Remember that 'deleting' an email doesn't immediately get rid of it. It then goes into a 'Deleted' folder. If you want to get rid of it completely you need to go into that folder and delete it for a second time.