Based on the level of respect or formality, you can say "I would like to call you" in Korean in 3 ways:

• Informal: na-neun neo-ege jeonhwoa-hago-sipeo (나는 너에게 전화하고싶어)
• Formal: jeo-neun dangsin-ege jeonhwoa hago sipeoyo (저는 당신에게 전화하고싶어요), jeo-neun dangsin-ege jeonhwoa hago sipseupnida (저는 당신에게 전화하고싶습니다)
• Very Formal: jeo-neun dangsin-ege jeonhwoa hago sipseupnida (저는 당신에게 전화하고싶습니다)

- I: na-neun (나는), jeo-neun (저는)
- would like to call: jeonhwoa-hago-sipda (전화하고싶다)
- you (indirect objective): neo-ege (너에게), dangsin-ege (당신에게)

Please refer to How to pronounce Korean Alphabet for the English pronunciation in this answer.