subquery with 3 different tables using ilike in postgres

Personal I have a question. How do I search for a particular text using ilike to know if this text exists in 3 related tables. I tried to exist but did not give

CREATE TABLE metodo (
    id SERIAL NOT NULL,
    descricao CHARACTER VARYING NOT NULL
);
CREATE TABLE forma (
    id SERIAL NOT NULL,
    id_metodo INTEGER,
    descricao CHARACTER VARYING NOT NULL
);
CREATE TABLE acao (
    id SERIAL NOT NULL,
    id_forma INTEGER,
    descricao CHARACTER VARYING NOT NULL
);