Any player who has reached level 6 can create their own Clan. To do so, go to the game menu, then tap on "Clans". When you start creating your Clan, you have to enter its full name and pick a Clan tag. Note that the maximum length of the full name of the clan is 22 symbols. Clan Tag has only 5 symbols.
From the very beginning, a newborn Clan has a capacity of 25 players. You can expand it up to 150 players, adding 5 members after the amount of contributed currency meets the goal. The more people you want to get, the higher the price is. Every Clan member can help expand the clan by contributing silver coins (up to 40 members) or gold coins (more than 40 members) to the Clan bank. Additionally, the Clan President will be able to make contributions in Clan coins. Once you finish creating your clan, you will become its President.
There are two types of clans: private Clans and open Clans. In private Clan players can join only when they receive an invitation from the Clan President or Vice President. In open Clan — players can join if they meet the requirement of this clan (a certain rating).