신청하다([sin-cheong-ha-da/apply]) means submit request, file for, ask officially. In polite speech, say 신청해요([sin-cheong-hae-yo]).
신청했어요([sin-cheong-hae-sseo-yo/applied]) is the polite past form. Example: 어제 비자를 신청했어요 (I applied for a visa yesterday).
신청해야 해요([sin-cheong-hae-ya hae-yo/have to apply]) means must submit. Example: 내일까지 신청해야 해요 (I have to apply by tomorrow).
신청하다([sin-cheong-ha-da/apply]) means "to apply". It is used when you submit request, file for.
1. Daily: “뭐 신청해요? (mwo sin-cheong-hae-yo)”
2. Past: 신청했어요([sin-cheong-hae-sseo-yo/applied]) applied.
3. Duty: 신청해야 해요([sin-cheong-hae-ya hae-yo/have to apply]) have to apply.
4. Warning: 신청하지 마세요([sin-cheong-ha-ji ma-se-yo/don't apply]) don't apply.
A: What do you apply for?
B: 비자를 신청해요. B: bi-ja-reul sin-cheong-hae-yo.B: I apply for a visa.
A: 비자를 신청해요? A: bi-ja-reul sin-cheong-hae-yo?A: You apply for a visa?
B: 네, 비자를 신청해요. B: ne, bi-ja-reul sin-cheong-hae-yo.B: Yes, a visa. - 신청하다([sin-cheong-ha-da/apply])
A: Did you apply?
B: 네, 신청했어요. B: ne, sin-cheong-hae-sseo-yo.B: Yes, I applied.
A: 언제 신청했어요? A: eon-je sin-cheong-hae-sseo-yo?A: When did you apply?
B: 어제 신청했어요. B: eo-je sin-cheong-hae-sseo-yo.B: I applied yesterday. - 신청했어요([sin-cheong-hae-sseo-yo/applied])
A: When do you have to apply?
B: 내일까지 신청해야 해요. B: nae-il-kka-ji sin-cheong-hae-ya hae-yo.B: I have to apply by tomorrow.
A: 내일까지 신청해야 해요? A: nae-il-kka-ji sin-cheong-hae-ya hae-yo?A: By tomorrow?
B: 네, 내일까지 신청해야 해요. B: ne, nae-il-kka-ji sin-cheong-hae-ya hae-yo.B: Yes, by tomorrow. - 신청해야 해요([sin-cheong-hae-ya hae-yo/have to apply])
• 신청하다([sin-cheong-ha-da/apply]) apply / request
- 신청했어요([sin-cheong-hae-sseo-yo/applied]) applied
- 신청하고 싶어요([sin-cheong-ha-go si-peo-yo/want to apply]) want to apply
- 신청해야 해요([sin-cheong-hae-ya hae-yo/have to apply]) have to apply
- 신청하지 마세요([sin-cheong-ha-ji ma-se-yo/don't apply]) don't apply