We form the passive voice by using ser + past participle.

E.g: Tú eres admirado. / You are admired.

Yes, it does change. It becomes an adjective, so it agrees in gender and number with the subject.

See the explanation

We use the present subjunctive after the:

Present
Command form
Present perfect
Future

We use the imperfect subjunctive when the verb in the main clause is in the:

Preterite
Imperfect
Pluperfect
Conditional

We use either the imperfect subjunctive or the pluperfect subjunctive.

We form the conditional perfect with the conditional of haber + the past participle of the verb

E.g: Yo habría comido / I would have eaten

We use the past perfect subjunctive in the si clause:

Si hubieras comido / If you had eaten

We use the conditional perfect.

E.g: Yo habría ido / I would have gone.

Yo habría ido
Tú habrías ido
Él, ella, Ud. habría ido
Nosotros habríamos ido
Vosotros habríais ido
Ellos, Uds. habrían ido

I would have gone
You would have gone
He, she, formal you would have gone
We would have gone
You would have gone
They, fomal you would have gone