It means kill yourself but a pg and is a more technologically advanced saying so it more suited to present day
Jane: ~is annoying~

Issy: Delete yourself
by Forissy December 15, 2018
said to make someone go away; to leave. Often used when angry at a specific person
I'm so sick of your bullshit Simon! Why don't you just delete yourself!!
by lotuspanda March 15, 2008