。
You may invite anyone who wants to come.
Literal
Come-want [attributive-の] person [if-なら] anyone invite [OK-よろしい].
招待する is the formal suru-verb for 'invite' (a colloquial alternative is 招く). The ~たい人なら誰でも frame combines the desiderative + 人 ('person who wants to') + the topic-based なら conditional + 誰でも ('anyone'), forming an open-ended permission. ~てもいい closes with 'it's OK to.'