jigeum jeonhwareul hago isseoyo.

지금 means “now” and functions as a time adverb in Korean. You can place it:

• At the very beginning for emphasis: 지금 전화를 하고 있어요.
• Directly before the verb or verb phrase: 전화를 지금 하고 있어요.
  Placing it after the verb (e.g., 전화를 하고 있어요 지금) sounds unnatural.

Korean marks direct objects with -을/를:

• 을 after a consonant-ending noun
• 를 after a vowel-ending noun
  Since 전화 ends in the vowel ㅏ, you attach 를 to get 전화를. This tells you that “call” is what you’re doing (i.e. the object of -하다).

전화하다 is a compound verb made of:

• 전화 (Sino-Korean noun for “telephone” or “phone call”)
• 하다 (“to do” or “to make”)
  Together it means “to make a phone call.” Conjugation follows regular -하다 patterns:
• 전화해요 (present polite)
• 전화했어요 (past polite)
• 전화할 거예요 (future polite)

The structure verb stem + -고 있다 indicates an action in progress (like English “-ing”). Steps:

1. Take the verb stem: 하 (from 전화하다)
2. Add -고: 하 + 고 → 하고
3. Add 있다 and conjugate politely: 있어요
   So 전화하고 있어요 = “I am making a phone call right now.”

You can adjust the politeness/formality of -고 있다 just like other verbs:

• Casual: 전화하고 있어 (to close friends or family)
• Polite (standard): 전화하고 있어요 (to acquaintances, strangers)
• Formal: 전화하고 있습니다 (in announcements, news broadcasts, business)

Yes, in very informal spoken Korean some drop particles for brevity:

• 지금 전화를 하고 있어요 → 지금 전화 하고 있어
  However, this is colloquial and not recommended in writing or polite settings.

Yes. A common shortcut is 전화 중이다 (“to be in the middle of a call”):

• 지금 전화 중이에요.
  You can also say 전화를 하는 중이에요, but 전화 중이에요 is more natural in speech.