This grammar pattern is used when we talk about a simple condition or a easy solution. ‘되다’ means in this pattern ‘to be enough’. ‘-으면 되다’ i’s attached to the word stem ending in a consonant other than ‘ㄹ’ and ‘-면 되다’ is attached to the word stem ending in a vowel and ‘ㄹ’.
● 한 달 생활비는 30만 원이면 됩니다.
● 여기에다가 이름만 쓰면 돼요?