Preparation

The preparations for Ihram are as follows; comb your hair, shape the beard, trim your mustache, cut your nails, and remove unwanted body hair.

Narrated Abu Huraira: I heard the Prophet (SAW) saying. “Five practices are characteristics of the Fitra: circumcision, shaving the pubic hair, cutting the mustaches short, clipping the nails, and depilating the hair of the armpits.” Sahih al-Bukhari 5891

Purification

You should perform Ghusl, a highly recommended act for those intending to assume Ihram. It is Sunnah for every man, woman and child, including those women experiencing menses or post-natal bleeding, to bathe prior to donning the Ihram garments.  A woman experiencing menstruation may fulfill all the rituals of Hajj except Tawaf of the Kaaba and the two Rakats of Nafl accompanying it.

Narrated Abdullah ibn Abbas:

The Prophet (SAW) said: A menstruating woman and the one who delivered a child should take a bath, put on ihram and perform all the rites of hajj except circumambulation of the House (Ka’bah) when they came to the place of wearing ihram.

Abu Ma’mar said in his version: “till she is purified”. The narrator Ibn Isa did not mention the names of Ikrimah and Mujahid, but he said: from Ata on the authority of Ibn Abbas. Ibn Isa also did not mention the word “all (rites of hajj).” He said in his version: All the rites of hajj except circumambulation of the House (the Ka’bah). Sunan Abi Dawud 1744

Ibn Abbas narrated :

(that the Prophet said): “The women in past-natal bleeding and menses were to perform Ghusl, enter Ihram and carry out all of the rites except for Tawaf around the House, until they becomes clean.” Jami` at-Tirmidhi 945

It is Makruh to neglect the Ghusl without a valid reason. If, for whatever reason, Ghusl can’t be performed, Wudhu should be carried out.

One must also focus on internal purification; by constantly making sincere repentance for ones sins.

Source: http://www.hajjumrahguide.com/hajj_stepbystep.html and https://hajjumrahplanner.com