We had set up a branch office in Japan, we would like to open another account. Can I register or subscribe the quick book account in Singapore ?

You may have two options:

1. Opening a QBO Global version for Japan

https://quickbooks.grsm.io/Japan

2. Opening a QBO Singapore version

https://quickbooks.grsm.io/Singapore

I would recommend the first one to let JPY as the home currency by default. You may consider purchasing a 3rd party consolidating app later if required.