If you are following a wheat free or gluten free diet, and you want to use soy sauce, it's essential that you source the correct type as regular soy sauce is fermented with wheat.
When checking recipes or readymade products that are wheat free and gluten free they should only contain Tamari, a wheat free version of soy sauce. If "soy sauce" is listed in the ingredients then it will contain the wheat fermented soy sauce.
Do not use regular soy sauce in wheat/gluten free cooking as it contains wheat.
Anywhere that soy sauce is required substitute wheat free Tamari, but make sure you use specifically labelled wheat free Tamari, not regular Tamari which does contain wheat.