。
She has to go there.
Literal
She [topic-は] there [to-へ] must-go.
~なければならない is the standard 'must / have to' construction — built from a negative ない + conditional ば + the verb なる ('become') with negation. Literally 'unless [she] does X, [it] won't become' — 'it won't do unless...'. This compound expression is one of the most common items in Japanese grammar; casual contractions include ~なきゃ and ~なくちゃ for everyday speech. Note the へ on そこ marking direction. The whole sentence is bare necessity — no agent specified for who's doing the requiring, just 'she has to'.