Konnichiha-Hello, but you should check japanese greeting system, it's much more complex than english one.
You can use and "Hajimemashite" before introducing yourself to somebody.
Watashi ha X desu. - My name is..
OR Watashi no namae ha X desu.
OR you can simply say: X desu.
X kara kimashita!- I am from..
Yoroshiku onegaishimasu!- Nice to meet you!
In this context "ha" is read as "wa".
And on X places your should add your name or name of your country!
Hopefully I helped you! :)