Your Netscape Editor will allow you "vary" the Size if the TEXT in your Web Pages.

Type some Text into the Netscape Editor Window...,
"Hold down" the Left Mouse Button and highlight "that portion" of the text for which you would like to change the Size.

From the Netscape Editor Toolbar..., "click-on" the Set Font Size Button...,

...then "click-on" the Appropriate Size.

You can also "Click-on" the Text Larger or Smaller Buttons to Increase the size or Decrease the font size on increment at a time. ( the A- or the A+ to the left of the Set Font Size Button)  Try it!

You can set the Font Size before you begin to type by "putting the Curser where you want" in the Editor Window..., then set the Font Size by "clicking-on" the appropriate size. Then begin to type!