emails to address book

[wendyl]

On my PC all emails I receive (after removing spam etc) and addresses I send to automatically are saved to my address book (I use Thunderbird now but this was the case before) I can't remember how it was set up but I want to set up the same arrangement on my husband's PC ( he also uses Thunderbird now). Please could someone either how to do this or point me to a relevant site/page - many thanks