greeting card
A card sent to convey greetings, often for seasonal occasions, New Year, or formal announcements.
I sent New Year's greeting cards to my relatives.
The company sends greeting cards to its business partners.
グリーティングカード is a loanword often used for Western-style greeting cards, while 挨拶状 is more traditional and formal.
Compound of 挨拶 (aisatsu, 'greeting') and 状 (jō, 'letter' or 'card').