I would really like to know the prepositions that must be used with the word "information".
1. We provide contact information for/of? relevant offices.
2. We give you information about/on? travelling to Europe.
3. The website informs you about/on English as a Second Language.
I get constantly confused about which preposition to use.
"Information on" or "information about". There's no difference in sense, really, but "information about" is the more traditional expression, and is better, I think.
We give you information about travelling to Europe.
The website informs you about English as a Second Language.
The sentence "we provide contact information for the relevant offices" is poor.  Do the data describe the addresses and telephone numbers of the relevant offices, or  is the contact information handed over to the offices? Sense  is the usual meaning, but the sentence remains confusing. These are better:
We provide the relevant offices with contact information <--- Contact data are given to the relevant offices.
We provide the contact information of/about the relevant offices. <--- Sense . Still not a very good sentence, but the best of a bad bunch. Really it's better to say:
We can tell you how to contact the relevant offices.