The salt won’t affect the flavor of your eggs; it helps solidify the proteins within the egg, helping create an easier to peel egg! I have used both iodized (table) salt and Himalayan rock salt (the pink salt in my photo) and both have worked perfectly.
Test one egg first, if for some reason it’s a bit undercooked, put eggs back and bring to boil, turn off heat.
You need to fully cover eggs with at least 2 inches of water for this to work. less water means that it will cool down quicker and your eggs won’t cook throughly.