Linen spray isn't a starch but smells nicer than plain water to spritz fabric before ironing.
The vodka is to kill any germs in your water so if you keep the EO and water for a while it won't grow nasties (bacteria).
Shake well before using. It adds a nice scent to linens when sprayed before bedtime and the alcohol evaporates so it dries faster.
Some EO's will discolor fabric so test before using.