BEST PAPER GREETINGS36 Pack Blank Thinking of You Cards Assortment Box with Envelopes, 6 Doodle Designs (4 x 6 In)

Are these note cards, where you just write on the back, or are they like cards that open up for you to write inside?

Some of the photos show large, oddly-sized envelopes that will be expensive to mail. Could someone describe the size of the envelopes? Thx.

Do these cards include envelopes?