You can format document text as you type it, or after it has been typed, by selecting the text and applying the format. You can also format your text using pre-set heading styles, using Heading 1 for main headings, Heading 2 for sub-headings, etc.
You can format selected text to a heading style using the Normal text box on the toolbar, or choosing Format, Paragraph styles and the required style from the menu bar.
You can also use the following shortcuts to apply styles:
To update the format of a style in the document:
Apply the style to a paragraph of text in the document
Manually update the paragraph of text to match the new style requirements
Click on the Style box on the toolbar
Position the mouse over the style you have applied to the text and click on the arrow displayed
Choose the Update to match command
To set the format for the entire document, you can change the Normal style that applies to all paragraph text in a document.
To set the Normal style:
Select a paragraph of text that has the required font applied to it
Click on the Style drop-down list on the toolbar
Click on the arrow to the right of the Normal font
Choose Update Normal text to match
You can now set the default font for all Google Docs as follows:
Click on the Format menu along the top of the screen
Choose Paragraph Styles
Choose Options
Choose Save as my default styles
A message across the top of the screen will confirm that your default styles have been set: