The correct way to write it should be "postcard".
A postcard is a type of card with an image that can be sent directly without an envelope, with text written on it.
The advantage of postcards is that they do not use envelopes, but the disadvantages are that they are small and not secretive, and the content written is open and can be seen by others.
Because the content of this kind of letter usually does not involve privacy concerns, and the content written can be seen by others, it is called a clear letter.
And the word "postcard" does not exist, it is a misspelling.
Postcards are a very special way of communication, it can be directly posted, without the use of envelopes, it is a convenient and fast way of communication. Postcards are usually printed with beautiful patterns and colors that give a visual treat. Writing words of blessing on a postcard can convey love and longing for loved ones and friends.
Compared to traditional letters, postcards are more concise and clear, and the content is clear at a glance and can be read without opening the envelope. At the same time, postcards can also be used to convey commercial information, promotional advertisements, etc., which is a very practical business communication tool.
While postcards have many advantages, there are also some disadvantages. Because postcards are small, they can't write much, and because they don't have privacy, what they write can be seen by others, so they can't be used for privacy communications.
In conclusion, postcards are a very special and practical means of communication, which can be directly posted, concise and clear, convenient and fast, with beautiful patterns and colors. Although there are some drawbacks, it is still widely used as a way for people to pass on their messages and feelings.