In order of best, second best, and third best, these are the ways of extending greetings of peace:

1) “Assalaamu ‘Alaikum Warahmatullahi Wabarakaatuhu”: Peace as well as the mercy and blessings of Allah upon you.

2) “Asslaamu ‘Alaikum Warahmatullah” : Peace and the mercy of Allah (swt) upon you

3) “Assalamu ‘Alaikum”: Peace upon you.

This order is proven by the narration of Abu Hurairah (RA), in which a man passed by the Messenger of Allah (saas) – who was seated in a gathering – and said, “Assalaamu ‘ Alaikum.” The Prophet (saas) said, “Ten good deeds (are Written for him).” Another man passed by and said, “Asslaamu ‘Alaikum Warahmatullha,” and the Prophet (saas) said, “ Twenty good deeds.” Then another man passed by and said, “Assalaamu ‘Alaikum Warahmatullahi Wabarakaatuhu,” and the Prophet (saas) said, Thirty good Deeds (Related by Al-Tirmidhee (2689), who said, “the Hadeeth is Hasan Saheeh)

Allah (swt) said in Quran:

“When you are greeted with agreeting, greet in return with what is better than it, or (at least) return it equally” (Qur’an 4:86)

It’s a Humble request Brothers to spread Greeting as it is to get Reward from Allah (swt) (without making shortcuts)

Jazak Allah Khair