It means you have to be issued the new stamp on your passport with the new durations on its, but it has maximum for 3 months by now.
It means you will have new length of stay in Vietnam and it has also maximum for 3 months.
There are some steps you need to follow to apply for Vietnam visa extension:
Please send the scans of your passport containing the original visa and current visa to our email at vietnamvisabooking@gmail.com, then we will give you a detailed advice for your specific case and the service fee as well since the visa extension varies for each case.
After getting the suggestions from our consultant staff, you are pleased to send your passport to our office here. If you are in Hanoi, we are pleased to come in person to pick up your passport at your address on your request.
The service will take 5 - 7 working days to complete or 3 working days in rush processing, which you are requested to pay more US$30 to normal processing service fee
You can also visit the Vietnam Immigration Department directly to apply for your visa extension. However, to avoid wasting your time and confusion about visa extension procedures, we do recommend that you should use our service instead of applying by yourself. Here below are the address of Vietnam Immigration Department in Vietnam:
In Hanoi: No. 40A Hang Bai Street, Hoan Kiem District, Hanoi
In Danang: No. 7 Tran Quy Cap Street, Da Nang
In Ho Chi Minh City: No. 254 Nguyen Trai Street, District 1, Ho Chi Minh City