There are too many possibilities.
I just wanted to add some more versions.
Whenever you need me, you can lay your head on my shoulder (figurative)
If you need additional/further information, don't hesitate to ask me (rather informal).
Anytime you need a friend (or information), I'll be here (extracted from a Mariah Carey's song).
I would be immensely grateful if I could be of any help (rather formal).
And so on. I love fancy versions.
Généralement, les gens qui savant peu parlent becoup, et les gens qui savant beaucoup parlent peu.: Generally speaking, the people who know little speak a lot and the people who know a lot speak little. - Rousseau