Registration Mail: Password.

Hello
 
 When a new user is registered by the admin, I create a pasword and this password is sent to the e-mail with the user. I would like to change the method. Instead of creating a password by the admin, I would like that joomla creates a random one and send it to the e-mail or better than this, not creating a random password and send a link or similar to the user and that the user create a new one

Is there a method to establish a format of the password(Capital letter, numeric characters,...)

Leave the password field empty and it will generate a password. Be sure you're using CB > User Management and not Joomla's user management. When creating them I recommend also ticking the Reset Password checkbox so on first login they'll be required to provide a password.

adn the password is sent to the user by email. But is there a method to to send a link? And to set a password format, that is, 12 chracters, 1 number, 1 symbol,...) ?

There's no method in Joomla to send a link for new accounts, but forgot login does use a link. Randomized passwords format also cannot be changed. New passwords manually entered can be restricted to a format though by adjusting the validation on the password field in CB > Field Management, but this does not apply to randomly generated passwords.