Do they wear special clothes in the quaker church?

Answer 1

The short answer is no, but the question surely arises from the fact that during the second period of Quaker history, at the outset of the 18th Century, and known as The Quietist Period, a concern against ostentation and vanity led Quakers to adopt what amounted almost to a uniform and enforced its wearing on more reluctant members. Margaret Fell, the only surviving Early Quaker unsuccessfully opposed the practice as a "silly poor gospel"

While later Quakers see this period as one in which the deadly hand of legalism was felt, they recognise also that the discipline upheld high standards of moral behavior and protected against undue compromise of basic Christian principles. Quakers were known to be honest and for this, flourished in business. It was the period which set the pattern for the Quaker form of worship, based of silence.