You won't find any automated way to delete a Roblox account on its website. Use one of the 3 methods listed in the post to delete Roblox.

How to Add or Remove Friends on ROBLOX? It’s likely that if you’ve been playing multiple games on ROBLOX, that you’ve found someone that is friendly and worth playing with more often.

You can delete a Roblox account by simply emailing the company, but there are a few other ways to do it.