Actively introducing or connecting someone to others
When to use
Directly introducing a person, Introducing a friend to a company, Introducing a resume
The nuance
Used when the subject actively introduces someone else. Expresses an active action.
소개하다 (so-gae-ha-da, sogaehada) · 소개되다 (so-gae-doe-da, sogaedoeda)
소개하다 (sogaehada) means actively introducing someone, while 소개되다 (sogaedoeda) describes being introduced passively by someone else.

One lane per word — no nested boxes, just the gist.
Actively introducing or connecting someone to others
When to use
Directly introducing a person, Introducing a friend to a company, Introducing a resume
The nuance
Used when the subject actively introduces someone else. Expresses an active action.
Describes the passive situation of someone being introduced to others
When to use
Being introduced to others, A new employee being introduced at a company, A resume being presented
The nuance
Used when the subject is being introduced by someone else. Expresses a passive state.
저는 친구를 회사에 소개했어요.
jeo-neun chin-gu-reul hoe-sa-e so-gae-haess-eo-yo., jeo neun chin gu reul hoe sa e so gae haess eo yo.
소개하다 is correct because it expresses actively introducing someone.
저는 친구를 회사에 소개되었어요.
jeo-neun chin-gu-reul hoe-sa-e so-gae-doe-eoss-eo-yo., jeo neun chin gu reul hoe sa e so gae doe eoss eo yo.
소개되다 is passive and used when the subject is introduced, not introducing others.
그는 신입사원으로 소개되었어요.
geu-neun sin-ip-sa-won-eu-ro so-gae-doe-eoss-eo-yo., geu neun sin ip sa won eu ro so gae doe eoss eo yo.
소개되다 is correct because the subject is being introduced.
그는 신입사원을 소개되었어요.
geu-neun sin-ip-sa-won-eul so-gae-doe-eoss-eo-yo., geu neun sin ip sa won eul so gae doe eoss eo yo.
소개되다 is passive; here the subject is introducing, so 소개하다 is correct.
이력서를 소개했습니다.
i-ryeok-seo-reul so-gae-haess-seup-ni-da., i ryeok seo reul so gae haess seup ni da.
소개하다 is correct because it expresses actively presenting the resume.
이력서가 소개되었어요.
i-ryeok-seo-ga so-gae-doe-eoss-eo-yo., i ryeok seo ga so gae doe eoss eo yo.
소개되다 is correct as it expresses the resume being introduced passively.
저는 선생님을 친구에게 소개했어요.
jeo-neun seon-saeng-nim-eul chin-gu-e-ge so-gae-haess-eo-yo., jeo neun seon saeng nim eul chin gu e ge so gae haess eo yo.
소개하다 is correct because it shows active introduction.
저는 선생님을 친구에게 소개되었어요.
jeo-neun seon-saeng-nim-eul chin-gu-e-ge so-gae-doe-eoss-eo-yo., jeo neun seon saeng nim eul chin gu e ge so gae doe eoss eo yo.
소개되다 is passive and inappropriate here because the subject is introducing.
Which word to use when actively introducing someone?
Which word fits when someone is being introduced to others?
Fill in the blank: '저는 친구를 회사에 ___.'
Fill in the blank: '그는 신입사원으로 ___.'