Grammar is simple. All you need is this one Golden Rule.
Subject -> Verb -> Object
Passive Voice vs. Active Voice is a popular grammar rule and debate. It can be explained in a million complicated ways. But the underlying problem with passive voice is that it violates the Golden Rule.
(I searched the web for some examples of passive voice vs. active voice. All the examples I found were boring and quite forgettable, so I wrote some new ones to help myself remember.)
Ex 1) Passive: The boy was given secret cuddles by the girl.
Active: The girl gave secret cuddles to the boy.
Ex 2) Passive: The farm was seized by mutant lamas.
Active: Mutant lamas seized the farm.
Ex 3) Passive: I was invited by aliens to try some intergalactic cheesecake.
Active: Aliens invited me to try some intergalactic cheesecake.
Ex 4) Passive: Beer, socks, and robot puppies are three luxuries that Frank could never live without.
Active: Frank can’t live without these three luxuries: beer, socks, and robot puppies.
Ex 5) Passive: Lamps are loved by me.
Active: I love lamps.
Of course, Passive Voice isn’t always bad. Sometimes it’s appropriate. But the danger is that it confuses the subject and the object, and can leave the reader confused about what’s happening. If you stick to Subject -> Verb -> Object, then you'll be two steps ahead of the competition.
As a writer, you want to make the reader’s job EASY.
Don’t leave your readers naked and alone with a crumpled map in the middle of a death maze.
Pave a yellow brick road for your reader, with rainbow railings on either side, and throw in a unicorn guide for good measure.