Thank you for uploading the image as it clearly displays mealybugs, common insect pests of indoor plants.

Yes, they can spread to your other indoor plants. (A hint to avoid problems indoors: Whenever you obtain a new plant, isolate it for at least a month even as you check periodically for unrecognized hitchhiking insects and or diseases.)

Mealybugs move very slowly. They normally develop a white, waxy coating which tends to repel certain pesticides. Even so, you can easily kill them with direct hits of alcohol, applied as a fine spray; repeat as needed.

Please be aware that jade plants are succulent plants. As such they are extremely sensitive to certain pesticides. Before you obtain any other product as a remedy for them, ask the retailer if the product is safe to use on succulent plants grown indoors.