The ʿUmrah or (Arabic: عمرة ) is a pilgrimage to Mecca performed by Muslims that can be undertaken at any time of the year. In Arabic Umrah means to visit a populated place. As a technical term used in the Shariah, Umrah means to perform Tawaf of Kaabah and Sa'i between Al-Safa and Al-Marwah, after assuming Ihram, either from a Miqat or a place in Hill. It is sometimes called the 'minor pilgrimage' or 'lesser pilgrimage', the Hajj being the 'major' pilgrimage and which is compulsory for every able-bodied Muslim who can afford it. According to some schools of Islamic thought, the Umrah is not compulsory but highly recommended.

Umrah is visiting Kaa'ba other then Hajj period.
For how to perform and what to do this you can find in some good religious guide on Islam or when you go it the travel agent will provide you with all details.
May Allah fulfill your desire and mine too. Aameen.

The Umrah is a pilgrimage to Mecca performed by Muslims. This pilgrimmage can be undertaken at any time of the year, unlike Haj which has a specific period. The Muslim has to perform 'tawaf' of Kaabah and 'sa'i' between Al-Safa and Al-Marwah, after assuming Ihram, either from a Miqat or a place in Hill. Umrah is not compulsory for a Muslim like Haj is.