Wazuans have jokes!

Both are OK. Depends on what your wife prefers.

You need an expert MCH/FP nurse to do both though. An implant (Jadelle) done badly will be uncomfortable to her (can be felt at the upper arm). An IUD placed wrongly can be displaced (causing pregnancy). So as a man always feel for the strings that hang out of the cervix during landing (Ehhh you have to have a pinetree of adequate length to feel them . Or use a finger.)

Some IUDs and all implants are hormonal, so consider the effects of hormones on her (if she has conditions such as obesity, diabetes, hypertension, allergy to hormones, she smokes, migraine headaches etc then she cannot use hormonal contraceptives).

There must be an FP clinic near you that does FP counselling for couples.

You could also try vasectomy.