For PC's - Internet Explorer & most other browsers

        To increase/decrease entire Web Page

Increase size (zoom in)  - Crtl and + sign (hold down the control key and press the plus sign)

Decrease size (zoom out) - Crtl and - sign (hold down the control key and press the minus sign)

                            OR

      To only change the text portion of the Web Page

For Mac's - Safari

        To increase/decrease entire Web Page

Increase size (zoom in)  - Command and + sign (hold down the command key and press the plus sign)

Decrease size (zoom out) - Command and - sign (hold down the command key and press the minus sign)

                            OR

      To only change the text portion of the Web Page