Customize Error/Success Messages in Drupal 7 I need to customize the success/error message after submitting details. It needs to cover areas like contact form, forum create etc.,

Especially below message,



Drupal Version : 7.57

Theme : Bootstrap

Also, Is there is any possibility defining a new style for above messages?
This might be what you are looking for:

Using the String Overrides module replaces the current string with what ever given.