You are talking about creating an entity for good health, right?
There are many ways to create entities, thoughtforms, servitors.
It is a large undertaking and requires much energy, i suggest you become familiar with techniques of sigilization. Using sigils to represent/ symbolize your intent i find is the best, and most precise way of doing things, so as to not make mistakes.
With these sigils, it can be as simple or as complex of a function you like. If it's for good health in general, then the sigil will be general, but the results will also be general and at first, marginal.
It's good to specify, if only a little bit. For instance: eating healthy, exercising often, being positive and feeling good about oneself all contribute to health, amongst other things.