How do arthropods give birth?

Answer 1

Arthropods include an incredibly diverse group of taxa such as insects, crustaceans, Spiders, scorpions, and centipedes. There are far more species of arthropods than species in all other phyla combined, and the number of undescribed species in the largest assemblage of arthropods, the insects, probably numbers in the tens of millions. Members of the phylum have been responsible for the most devastating plagues and famines mankind has known. Yet other species of arthropods are essential for our existence, directly or indirectly providing us with food, clothing, medicines, and protection from harmful organisms.

Answer 2

Most arthropods lay (and then abandon) eggs ("oviparous"). Some carry around the eggs for significant amounts of time, then release them around the time the larvae hatch, like lobsters. Spiders often make an egg sac which maintains humidity, containing thousands of eggs, which is hidden or carried until hatching.
There are exceptions to egg-laying, scorpions are a notable one with young born live (ovoviviparous) one at a time and carried around on the mother's back, and upon whom they are dependent until at least the first moult.