please i want visit China with my Kids for holidays

You need t apply for separate visas for mainland China and HK respectively.
First, prepare the relevant documents: passport and the copy, the application form, a passport-style photo, financial support proof, flight tickets and hotel booking record, an introduction letter, and the invitation letter.
Next, submit the application to China embassy to apply for China tourist L type.
For HK visa, you should prepare travel itinerary, copy of passport, the application form, a passport-style photo, financial support proof, flight tickets and hotel booking record, and then submit the application to China embassy to apply for HK tourist visa.