Creating an Alliance
If a player is level 20 or higher and wishes to create an alliance, that player may click on the "Alliance" button in the top right corner of the game screen and, in the bottom of that window, select "Create Alliance."
Once this option has been selected, a new window will pop up and the player will be allowed to choose the alliance's name, tag, description, and emblem. The "Alliance Tag" is usually a shortened version of the alliance name, often an acronym, and is made up of 2-5 all-capital letters. The "Alliance Emblem" is an icon that will appear over the alliance members' bases to signify that they are part of the same alliance. Players are not able to change the alliance name, tag, or emblem once this form has been completed.
How To: Alliance Bonuses