Minecraft Armor Stand doesn't do much on its own. Using a special book, you can adjust any of it to your liking from poses to visibility.
Obtaining the special book
Get yourself a Book and Quill and then sign it with the title "Statue". Whether the book is empty or not is not important. After doing so, it will became enchanted and turned into what you need.
Using the book
The book contains around 10 pages worth of option that would otherwise be very cumbersome to explain here with only a bit of brain cells. To keep it simple, you can use the video below. The ordering of options might look a bit different, but functionality is about the same.
Credit: ZombieCleo from Hermitcraft SMP
One other thing you can use this book for is to customize item frames. You can toggle its invisibility (can also be crafted) and invincibility.
