The word "performance" refers to how well someone does something. People often talk about a person's "job performance", which is how well someone does their job:
I've been extremely satisfied with his job performance.
In the example at top, the writer doesn't use the phrase "job performance", but that is the kind of "performance" she is talking about. The sentence means "If you want to ask about Adele or how well she did at her job, please contact me.