Vietnam and China have more than one border gate, but the most famous and busiest one is probably Dong Dang international gate which connects Lang Son, Vietnam and Pingxang, China. The gate is usually open from early morning until at least 18:00, so you should plan your trip accordingly.
From the Chinese side of the border gates, you would encounter a building in which you have to go through some immigration process. To enter Vietnam, you must have your Vietnamese visa issued before your arrival. The typical visa type is Tourist Visa, which lasts for 30 days. Depending on where you get it from, the visa might expire sooner, but not later than that time period. However, no need to worry because once you enter the county, you can possibly ask for extension. The cost of Vietnamese visa varies tremendously in different countries. Therefore, if you have enough time, it is best that you get the visa from a Vietnamese embassy in Asia.
Another notice is that you must make sure that you have enough Vietnamese currency to enter the country and get to big cities because there is no ATM machine on either side of the Dong Dang gate. As soon as you enter Vietnam, go to the office and get all the stamps you need before going out to look for transportation to Hanoi.
A trip to Hanoi would cost you approximately 100,000 dong, which is equal to 5 dollars. You can get to the city by any way you want, but shared taxi might be the best choice to go with. However, a plethora of buses, trains and other means of transportation are available in Dong Dang international gate. Upon you arrival in Hanoi, 40,000 dong (about 2 dollars) should be enough for you to get from the bus station to the place that you’re staying.