How to write the calligraphy signature after writing it?

It depends on whether it is brush calligraphy or hard pen calligraphy.

For brush calligraphy, the traditional format is generally used. Signature can have a deposit. Common only the next paragraph, the format is:

Time (usually not Gregorian calendar)+(%location)+author+(respect) book

Such as: "Boxer Xia Yue, Ancient Style Hall XX Zun Shu".

In traditional calligraphy, dates are marked by years, and months are marked by lunar calendar, not specific to a certain day.

Hard-pen calligraphy, if arranged horizontally, can be in a modern format: XXX books on X month X day in 2020. If it is vertical, it should also be in the traditional format.