How do you make royal icing thick and thin

What you will need to make Royal Icing:

Instructions:

First, you put the egg whites in a bowl and add also the icing sugar until the consistency is and smoothe.
Then add the lemon juice. If you want a thicker texture for borders of biscuit, then I would recommend using a bit of lemon juice but If you are doing the technique flooding (where you fill the cookie on top) then I would use more lemon juice.
Once the Icing has dried share with friends and enjoy.