1. Manual signature: When paper bills are used, each bill is signed manually. This can be done by using a pen or other suitable tools. Make sure that the signature on each bill is clearly visible and consistent with the official signature.

2. Digital signature: If you use electronic bills, you can consider using digital signatures to handle multiple bills with the same content. Digital signature uses encryption technology to verify the integrity and authenticity of files. You can use related software or online services to generate digital signatures and apply them to each bill. This method can be more efficient and convenient.