The signature should be on the last line or the penultimate line to the right.
According to China Literature Network, the signature is written on the last line or on the right side of the penultimate line. The signature is the name of the person who sent the card, and then the date is written below the name.
The signature refers to the written content in the calligraphy work other than the main text. The signature includes: the source of the main text, the recipient of the gift, the reason for creation, the time of creation, the author's name and font size, etc.