What is a "vefk"? Is it permissible to make or have one made?

In Turkish, "vefk" means harmony, and refers to a shape—usually a rectangle—divided into sections in which certain numbers and letters are written. Those who make these claim that, through the vefk, Allah will assign a jinn to protect them. Islam strictly prohibits fortune-telling, talismans, and magic because they harm the belief in tawhid (the oneness of God) (el-Fetâvâ’l-Hindiyye, V, 459). Seeking help from jinn and devils, as well as using incomprehensible spells and talismans, are acts that can lead a person to shirk (associating partners with Allah) (Nevevî, el-Mecmu’, IX, 66). Such practices always involve deception, harm, and evil (Cassâs, Ahkâmu’l-Kur’an, I, 61).

Source: T.C. Diyanet İşleri Başkanlığı, Din İşleri Yüksek Kurulu