Many do it like this, and you get a liquid that is easy to distribute.

Mix an amount of Stevia White with cold water, stir, and put in the fridge. Some use a bottle with a pipette. E.g. a cleaned out bottle used for nosedrops.

Keeping a good check on the ratio of Stevia White and water (check a conversion table), you can make your own conversion table for the resulting liquid - and one drop may equal the sweetness of one tea-spoon of sugar.

Most of the other resellers of liquid Stevia extract, use distilled water in their solutions. Then, the solution has a limited shelf-life, and an opened container should be refridgerated.

Unfortunately, other resellers do not specify the amount of Stevia extract used in their solutions, but the goal is to have the solution equal a certain sweetness, e.g. one drop=one tea-spoon of sugar. Mixing our Stevia White is easy to do yourself, though.

Another advantage with Stevia White, is an eternal shelf-life!