Travelling to Kathmandu then planning for my fiance and I to travel to China, Shanghai.

How long would it take to get visa in Kathmandu, Looking for two single entry.
Planning to work in Shanghai before returning to UK. Have already invitation from parent company to visit/work.
I am British my fiance is Brazilian/Italian. I have visited China on several occasions she has not.
Can you get visa on the day or do you have to leave documentation in Kathmandu.

thank-you