I am asked to put in a word, where do you get the word ?

Is this the copy protection issue in games 3-5? That's been covered in other threads on this forum, but I think the answer is that there is a small document provided by GOG that installs with the game and contains answers to all the copy protection questions (i.e. where the game asks you for a specific word from the manual). The file is called keys_3_5.pdf and contains the answers for Might and Magic 3, 4 and 5.
If this is actually an in-game question, in which the answer is to be found somewhere else in the game or something, then you can check the cluebooks which are provided as extra downloadable content for the answer. You can grab those from your game library page on GOG by clicking on the Might and Magic pack. You should see some additional files you can download, one of which contains all the cluebooks. This is also where you can get the world maps for each game.

Tip: also mention in the subject which opus you are playing. This will make it easier to help you.
I played MM6 and do not remember of a castle Burbick. Sorry.

If you're referring to Castle Burlock from the Xeen games, then you only need the Crusader skill for all party members to enter. The word sounds like copy protection, and the previous posters have directed you to a resource to get past the copy protection.