Praise be to Allah, the Lord of the Worlds; and blessings and peace be upon our Prophet Muhammad and upon all his Family and Companions.

Hijab (a garment that covers the woman’s whole body) is an obligation for the Muslim woman. Allah says (meanings in English) {and to draw their veils all over Juyubihinna (i.e. their bodies, faces, necks and bosoms, etc} [24:31] It is prohibited for a woman, who believes in Allah and the Last Day, to uncover a little part of her body to alien men (those to whom marriage is permissible). Hijab should meet the following conditions: 1- It should cover woman’s whole body. 2- It should be thick enough. 3- It should not be transparent. 4- It should be loose. 5- It should not be decorated as to attract lookers. 6- It should not be similar the dress of men or the dress of unbelieving women. By the way, covering the whole body is not only better but also shows the best commitment to Islam.
Allah knows best.