U+2610 Ballot Box

The Wikipedia has the following information about this codepoint:

A checkbox (check box, tickbox, tick box) is a graphical widget that allows the user to make a binary choice, i.e. a choice between one of two possible mutually exclusive options. For example, the user may have to answer 'yes' (checked) or 'no' (not checked) on a simple yes/no question.

Checkboxes are shown as ☐ when unchecked, or ☑ or ☒ (depending on the graphical user interface) when checked. A caption describing the meaning of the checkbox is normally shown adjacent to the checkbox. Inverting the state of a checkbox is done by clicking the mouse on the box, or the caption, or by using a keyboard shortcut, such as the space bar.

Often, a series of checkboxes is presented, each with a binary choice between two options. The user may then select several of the choices. This is contrasted with the radio button, in which only a single option is selectable from several mutually-exclusive choices.

Checkboxes may be disabled (indicated "greyed out") to inform the user of their existence and possible use despite momentary unavailability.