How can you change the font size for an entire document?

The font size I picked for a letter I am writing is too small. I would like to increase it after it has been created (typed).

Be sure it is not a scale issue. Bottom right for change.

Hello @EdithWilson,

To increase the Font Size for your entire document, you could just press CTRL+A to select all text, and then set your preferred size in the Font Size listbox.

HTH, lib

This is direct formatting and not the smartest way to style documents.

If you actually “picked” the font size at the very beginning and never changed it, you may select the complete text (Edit > Select All) and then “pick” your new font size. That’s “direct formatting” of everything.

Much better: Use styles.

Open the stylist: F11 or Format > Styles and Formatting / Format > Styles and Formatting depending on your version.

Select all the paragraph styles you actually used and pick Modify from the context menu. Then change the font/size as you want. If you also used character styles do respectively.

If there is already direct formatting concerning font/size remove it first.

If you’re not yet into understanding styles - your font is probably coming from one paragraph type style called “default style” so it’s F11 then right click on that style then select your font size.

If you’re not yet into understanding styles, try and read tutorials on using Styles. Once you understand styles, you’ll never work without them.
And context15 is right, change the default style.

Came here for something else and that is:
How to increase all font size when multiple sizes are present in the document

The aforementioned methods (select all, set size to desired value) will change all fonts to that specific size instead of increasing/decreasing the individual sizes.

Solution

Press CTRL + [ or CTRL + ] or go to Format\ Text\ Increase Size or Decrease Size

Format > Increase/Decrease Size` applies direct formatting to the selected text range(s).
Always consider to create a consistent bundle of inheriting paragraph styles and character styles in your template. If font sizes are unchanged there or defined by a percentage (applied to the style the current one inherits from), you can make changes for the relevant ancestor with effect on every inheritor.