While learning to say how to say I love you all in Hindi, you need to take care of the persons you are saying this to.
It could be for somebody who is younger to you in age or authority or rank, etc., while it could be for people who are senior, elder and at a higher rank than you.
Recommended books to explore Hindi language more:
We are providing both the options and also providing the phonetic representation of both the versions.
While saying it to elders
While saying it to younger than you