What is the visa type of Lao Ni -B3? Can I postpone it locally? How about an extension? I want to stay there for 90 days. The visa can only stay for 30 days.

B3 is a tourist visa for Laos, with a maximum duration of 30 days. You can't work, so it is easy to sign.

It shouldn't be difficult to postpone the proposal to find China's agent in Vientiane (China City).

B2 is a business visa. You need an invitation to apply for it. You can work for up to 30 days. If it is postponed, you can apply for a temporary residence permit and work permit there. If you want to be lazy, you can find someone to help you.