There is a small group of adjectives, sometimes referred to as post nominal adjectives, which can only occur immediately after a noun. Examples are:
the president elect
the devil incarnate
Many other adjectives can be used immediately after a noun when they form part of a (reduced) relative clause, e.g.:
Let’s use the time available.
Is she someone capable of making difficult decisions?
I’d like to speak to all the people involved.
There are some adjectives which can occur either before or after a noun, but the position they occur in has an effect on their meaning, e.g.:
the concerned parents (= ‘the parents who are worried’)
the parents concerned (= ‘the parents who are involved/mentioned’)
the present situation (= ‘the situation which exists now’)
the people present (= ‘the people who are here/there’).
a responsible person (= ‘a person who is sensible/reliable’)
the person responsible (= ‘the person who is to blame or has responsibility for something’)