Whenever you can use your website to provide answers to clients’ questions (instead of typing out the answer in a response email to your client), then do it!
Here’s an example of what I’m talking about: Say I am responding to a client who has asked about my web design rates. In the body (text) of the email that I send to the client in response, I might write something like this:
Dear Client X:
Or you may reach me by phone at:
Thanks for your consideration.
This may seem like a simple thing, but it is effective in getting the message across to your client that consulting your website is likely to be rewarding for them, and that they will find useful information if they consult your website.
In fact, in general, it’s always good to provide some link (any link) to your website in the body of all emails you send to clients, even if the link you insert may not directly answer their question. It’s the click that you want — so providing the possibility of clicking to your website in a prominent place in your email is always a good thing in terms of marketing your website.