Generally speaking, the pen signature blue pen represents less important documents or occasions. This is because blue ink is usually used in less formal occasions, such as taking daily notes or signing some informal documents. In formal documents or contracts, black signature pens or carbon ink pens are usually used, because black ink can last for a long time and is clearer and easier to read than other colors.

However, this does not mean that the blue pen is only suitable for informal occasions in all cases. In some cases, the blue pen can also be used in formal documents and contracts if it is communicated with the other party in advance and recognized.

Generally speaking, the color of the pen should be decided according to the specific situation and actual needs.