These properties control the visibility and format of chart titles (Title, Subtitle, and Footnote). The following code shows the property names and default values:

title: {
   text: 'Chart Title',
   visible: false,
   align: 'center',  // One of 'left', 'center', 'right', 'chartFrame'
   font: 'bold 10pt Sans-Serif',
   color: 'black',
},

subtitle: {
   text: 'Chart Subtitle',
   visible: false,
   align: 'center',  // One of 'left', 'center', 'right', 'chartFrame'
   font: '10pt Sans-Serif',
   color: 'black',
},

footnote: {
   text: 'Chart Footnote',
   visible: false,
   align: 'center',  // One of 'left', 'center', 'right', 'chartFrame'
   font: '10pt Sans-Serif',
   color: 'black',
 },

Each axis also has a title object. For information, see Axis Properties.