Several have asked me what an Ember card is. Ember Days are the four sets of three days in Advent, Lent, between Pentecost/Trinity and in September set aside for special prayer and fasting. They have become associated with times for ordination, as prayer and fasting are apt preparation. Nowadays, it is customary to pray for clergy and those to be ordained at Embertide. [Embers are, of course, ashes!]
So an Ember card is an ordination card, and many ordinations send them to family and friends to ask for prayer. In the way of the modern world, they have become very fancy, over-elaborate, and sometimes plain self-indulgent. They are not change of address cards.
I have copied one off the internet and put it below. If you choose to do this, all you really need to give people is where and when you are being ordained, and which ministry you will be serving in.