it doesn't mean information. it means what time period you have to leave between notifying your current employer about your intention to leave, until the time you can actually leave. This would depend on your employment country. usually one, two or four weeks.

Here means....information

give notice = announce (通告) to the company,landlord, or similar, that you intend to leave give two weeks notice give one month's notice How much notice Geddit?

"How much notice do you have to give" is usually used with some event. It means: "How much time before the event do you have to inform (or warn) somebody." Example: "We're going to have to shut down the water in the building. How much notice will we have to give the employees?" Another possible meaning of "give notice" is to give your employer notice that you intend to resign. "I have found another job and gave my boss two weeks notice."