Is all Guild Wars 2 voiced

You do not need a charter or to go to a special area, though you can create a guild by speaking to a Guild Registrar in a city.

You will need to have 1 silver in order to create a guild. Then all you need to do is open the Guild window (G by default), choose a name (31 character limit) and guild tag (an abbreviation that will show up next to your character name, up to 4 characters), and that's it.

Note that guild members don't even have to have be on the same Home World (server) as you, though you do need to be on the same Home World if you wish to play World vs. World together.

The default maximize size for a guild is 50 members. In order to increase this size, you will need to speak to a Guild Registrar. The following table from the official wiki lists the costs and upgrades as follows:

Tier   Membership Cap    Cost
 1          50         1 Silver 
 2          100        1 Silver
 3          200       10 Silver
 4          300        1 Gold
 5          400        1 Gold
 6          500        2 Gold

In order to participate in guild functions such as Chat, as well as to take advantage of various guild perks, and to contribute towards guild progression, you'll need to Represent that particular guild.

You can do this by pulling up the guild menu, and clicking the "Represent" button at the bottom of the screen. Additionally, while you can join multiple guilds, you can only represent one at a time, so you won't be able to participate in guild chat from multiple guilds simultaneously.