Generate a password and insert it in-place.  Such functions provided:

password-generator-numeric  - generate PIN-code or any other numeric password.
password-generator-simple   - simple password for most websites.
password-generator-phonetic - easy to remember password.
password-generator-strong   - strong password and still suitable for most web sites with strange password requirements to used special chars.
password-generator-words   - generate rememberable password from top used 1500 english words.
password-generator-custom   - generate custome password from your alphabete.

Use C-u <length> password-generator-simple to specify length of generated password.  This works with other functions too.

See full docs here: http://github.com/vandrlexay/emacs-password-genarator