I have done this for the past couple of years and fell in love with this method of freezing green beans.
Wash the beans and cut off both ends, just like you see on the picture below.
Fill a pot with water and bring it to boil. Place the beans into the boiling water and press start on a 3 minute timer right away.
In the mean time, prepare a bowl with ice cold water where you will transfer the beans right away after the 3 minute timer beeps. Keep the water cool, you might have to add cold water or ice. You are trying to keep the beans from continuing the boiling process.
After you cooled your beans down, put them in labeled ziplock bag. I don't own food vacuum sealer so I use the straw method. you seal the ziplock bag until there is a tiny hole that you can only fit the straw thru and begin to suck air out of the bag until it looks "vacuumed".
This will assure you don't get freezer burn. Now that that's done, I can go on to do the same thing with my edamame.