In Shuozhou, if you are ordinary friends, you can only use the gift money to attend the banquet at home or in the hotel on your wedding day (ordinary friends are generally below 200 yuan).
If they are good friends, they should go to her house to help or something, which is better. After all, the relationship is unusual.
As for the red envelope, that is, the gift money, you have to pay it when everyone pays the gift money. There is usually a special gift collection before the lunch party. Good friend, 200 yuan can do it, or a little more, as long as you put your heart into it.
Of course, you are good friends. If you don't understand anything, you can tell her directly, so that you can communicate psychologically and understand the customs of Shuozhou, killing two birds with one stone.
I hope I can help you:-)