How do I get an email to open? When I click on it, it puts a check mark in the box beside it.?

Then most of the lettering turns blue.

How do I get an email to open? When I click on it, it puts a check mark in the box beside it.?
Click on the subject of the email to open it rather than the box beside it.
Reply:Click on its subject line usually in blue letters, not the box. When you put your cursor over the subject area, it underlines, click on it.