How to use regard and regards?
You can find good examples here:

Regards is often used to close communication such as email or letter. I suppose you could say it is a very formal way to say:

'Im thinking of you' or 'My thoughts are with you'

eg. Dear sir,

I am writing this letter to you....words.....words.....

If you require further assistance, please contact me on abc123.

Best regards



If I used 'Im thinking of you' to close an email to a client, they would most likely become alarmed. The meeting after would be quite awkward. ;o)