Hi phew,
It's a way to say, "That's all up to me" or, "These are things that I'm responsible for" or "These are the things I will take care of/ I will do"
For example, if I was studying a course and I got a bad grade because I didn't study, 'That's all on my end" - because it was up to me to study and I chose not to.
EDIT: I would also use it as Darren Quinn suggested too. (probably more so actually)
If I finish presenting at work and I have nothing else to say. "That's all on my end". AKA, "That's all I have from my side of the conversation"