2 Answers

Hold down on the Ctrl and tap the + key

or 

Make text larger Start button > control panel > Appearance and Personalization > Display > Make text and other items
larger or smaller

There are many different fonts available on your system. Your system preferences should have a font list in the configuration settings. You can go through your font list to select a style you like and size for various functions or programs possible. Each font style has a list of font sizes such 8 point, 10 point, 12 point and 14 point or even larger.  The style you choose also brings with it the variations in type sizing available for that font. So choose one that presents scripts that you can read comfortable. Some operating systems allow you to use many different fonts and font colors. This takes time to set-up usually and are not on my personal list of things to do that make my day. I prefer simple set-ups so I don't get busy working over variables all day.