Praise be to Allah.
Shaykh ‘Abd al-‘Aziz ibn Baz (may Allah have mercy on him) said:
Ramadan: The best month of the year
“The month of Ramadan is the best month of the year. Allah has chosen it to make fasting this month obligatory and the fourth pillar of Islam and He has prescribed for the Muslims to spend its nights in prayer. Prophet Muhammad (peace and blessings of Allah be upon him) said: “Islam is built on five (pillars): testimony that there is no god but Allah and that Muhammad is the Messenger of Allah, establishing prayer, paying zakah, fasting Ramadan and performing pilgrimage to the House (Ka`bah).” (Agreed upon)
And he (peace and blessings of Allah be upon him) said: “Whoever spends the nights of Ramadan in prayer out of faith and in the hope of reward, his previous sins will be forgiven.” (Agreed upon)
How to welcome Ramadan
I do not know of any specific way of welcoming Ramadan , but the Muslim should welcome it with joy and happiness and thanking Allah for enabling him to reach Ramadan , for He has caused him to be among the living who compete in doing righteous deeds.
Reaching Ramadan is a great blessing from Allah. Hence the Prophet (peace and blessings of Allah be upon him) used to give his Companions the glad tidings of the arrival of Ramadan and explain its virtues, and the great reward that Allah has prepared for those who fast and who spend the night in prayer.
And Allah knows best.