The eighteenth vow of Dharmakara states that being in any universe, one desiring to be born in Amitabha's Pure Land and calling his name even for ten times will be guranteed rebirth there.
Moreover, the Sutra explains that Amitabha finally achieved buddhahood and is still alive in his land of Sukhavati.The basic doctrines concerning Amitabha and his vows are found in the three cannonical text of the Mahayanas:
The Larger Sukhavativyuha Sutra
The Smaller Sukhavativyuha Sutra and
The Amitayurdhyana Sutra.
Through his true effort, he created the 'Pure Land'.