In HTML, a checkbox is an element that allows the user to select one or more options from a set of choices. Checkboxes are typically used in forms to allow the user to make multiple selections, such as selecting toppings for a pizza or choosing which features to include on a website.
To check an HTML checkbox, you can use the `checked` attribute. The `checked` attribute is a Boolean attribute, which means that it can only have two values: `true` or `false`. When the `checked` attribute is set to `true`, the checkbox will be checked. When the `checked` attribute is set to `false`, the checkbox will be unchecked.