。
She's liked by everyone.
Literal
She [topic-は] everyone [by-に] is-liked.
Japanese passive sentences mark the agent (the doer) with に: ここでは X に 好かれる = 'is liked by X.' Layer ~ている on the passive 好かれる and you get 好かれている — a present resulting state, 'is in the state of being liked.' Without the ~ている, the bare 好かれる would feel awkwardly bare or future-leaning; the aspectual marker is what produces the natural-sounding present meaning. 皆 ('everyone') as the agent is broad — the implication is general affection rather than a specific admirer.