Why did the British pass the Stamp Act?

The Stamp Act was simply an unfair money-generating policy. The British government decided that many printed materials should need a government stamp attached to them and that anything with these stamps would be taxed. This was one in a long line of unfair British tax attempts that increased the resentment between the Colonies and Great Britain.
The purpose behind this tax was to provide funding for soldiers who were being stationed in the Americas after the French-Indian war. After concluding the conflict, the British maintained an active military presence to prevent the threat of future invasion. The colonists, who were unconcerned at the possibility of an invasion, were angered at the new tax, which was perceived as an attempt to fund the British military without affecting the government's finances.