Correspondence cards should be postcard-sized [W6 x H4½ inches (15 x 11 cm)], and a printed on card of a minimum of 300 gsm.
They include the name, address, telephone number and, more frequently now, the e-mail address.
When a postal address is not permanent, the cards can be printed with just a name, mobile telephone number and email address.
Correspondence cards are always sent in an envelope.
A rarer, yet useful, addition is a folded card, known as an ‘informal’, sized W4 x H3 inches (10 x 7.5 cm) with the name printed on the front without any prefixes, for example, ‘Charlotte Debrett’. An informal can be used like a personal compliments slip.