Font Size

• 1). Open Mac Mail in your Dock or your Applications folder.
  
  
• 2). Click on "Preferences" in the Mail menu. Select "Fonts and Colors."
  
  
• 3). Select the size of the font you want to view all of your email in from the "Mailbox Font Size" drop-down menu. The font sizes range from 8 to 64.
  
  

Mail Window Size

• 1). Open Mac Mail on your computer. It is in the Dock or the Applications folder.
  
  
• 2). Click on "New Message" in the File menu.
  
  
• 3). Click on the lower right-hand corner of the Mail window and drag with your mouse to increase the size of the window.