Helvetica is not an option in Pagemaker 7

Helvetica is a Font (also known as a Typeface). It has absolutely nothing to do with Pagemaker. Pagemaker is just publishing software that will let you use any Fonts that are installed on your system. If you want to use the Helvetica Font, you need to own it first and have it installed on your system. Once it is installed on your system, programs (like Pagemaker) can make use of it.
Fonts, like other digital media (such as photos) are usually copyrighted by the authors who created them. Helvetica is a commercial font and if you don't own it, you can purchase and download it here: http://www.linotype.com/526/helvetica-family.html

you have to buy and download helvetica but if you look at arial it is quite similar with some small variations