What is the easiest & most economical way to travel to the Murano Islands from the St Mark's Square area?
On this link I have posted, you will find many options to get to Murano Island from Venice.
https://europeforvisitors.com/venice/articles/murano_transportation.htm
Just do not fall for one of the "free" glass factory tours offered by touts in the San Marco area, unless you enjoy the prospect of high-pressure sales tactics.
Just take the 4.2 vaporetto from the San Zaccharia stop.
A handy app to have on your phone in Venice is Chebateu (which boat). It links to the vaporetto timetables.
Plug in your departure and destination stops, and your arrival times, and the app gives vaporetto options.
Personally I like to walk to Fondamente Nove and take the vaporetto from there. If you're not familiar with Venice, then the vaporetto from San Zaccaria works but will take longer as you must circumnavigate the Lido.
If you're there while it's running (it's a seasonal route) the 7 gets you to Murano in 25 minutes from San Zaccaria.
You didn't ask, but I will volunteer that "B Restaurant" on Murano has great food and is reasonably priced. My friends and I ate there on Easter a couple of years ago and I was pleased to hear from a former co-worker that it is still very good (as of a few weeks ago).
Thank you all for the information & I love recommendations for where to eat. We are leaving in 1 week and I can't wait!! First time visiting Venice, Florene & Rome.