How Many Type of Shrines are there ?

A sacred shrine is better known as Mandala in Sanskrit. Generally it can be classified into four types:

Maha Mandala is one in which you can find pictures and images of all the Buddhas and Bodhisattvas. Since this is the assembly of all the great ones, the virtues are great and far reaching, therefore it is known as Maha (great) Mandala.

Samaya Mandala is one in which you can find the drawing of implements and mudras. Samaya means original vows.

Dharma mandala is one in which you can find the seed syllable and Mantra of all the Buddhas. A sacred shrine which displays works and scriptures is known as Dharma Mandala.

Karma Mandala is where you can find the images of all the Buddhas. It is used when performing rituals.

Different types of Mandala have different meanings:

Maha Mandala symbolizes the ten realms of existence.

Samaya Mandala symbolizes equality.

Dharma Mandala symbolizes the six senses.

Karma Mandala symbolizes the actions performed during ritual.

What are Garbhadhatu and Vajradhatu?

Garbhadhatu and Vajradhatu are known as the duo Mandala of Vajrayana Buddhism;
the dharma for attaining the Sidhi of Buddhas.
Vajradhatu, the diamond element of the universe, is the fruit attained by all Buddhas. It represents reasons or principles of such wisdom which can be interpreted as the effect.
Garbhadhatu, the womb treasury, is the universal source from which all things are derived. It represents the fundamental nature which can be interpreted as the cause.