* The knowledge and skill you need to use that power effectively come from your own hard work. coven training is the easiest and safest way to learn and to practice in a supportive context. Alternatively, you might seek individual training from an elder you respect. Be aware that the best training system accomplishes nothing unless you actually do the work. And there certainly are skilled and empowered Witches who are solitary and completely self-trained.
* Credentials come from other people. If community recognition is important to you, you should join a coven that is part of a lineage, one whose elders have traditional religious authority to bring others into that collective. If legal clergy status matters, look for a group that is affiliated with one of the duly incorporated organizations like Covenant of the Goddess. Of course, one coven can convey both types of credential -- as Proteus Coven does.
Be mindful, though, that power, skill, and credentials are three entirely separate things. No one of them can substitute for either of the others, nor prove that either of the others is also present.
Free eBooks (Can Be Downloaded):Tobias Johansson - The Crucible And The Reasons For The Salem Witch Hunt
Peter Henry Emerson - Welsh Fairy Tales And Other Stories
Wim Van Den Dungen - Enoch And The Day Of The End