성함 is the formal form.
이름 is the polite form.

To ask, “What is your name?” in the formal form, use the subject particle 이 plus 어떻게 되세요?

성함이 어떻게 되세요?

For the polite form, use this:

이름이 뭐 예요?

To answer, simply use the standard form of name 이름.

제 이름은 김지니예요.

Subject markers mark the subject. In this case, I think it’s more close to “topic”.

Topic markers in Korean are:

은 and 는. They are appended to nouns. If the final syllable is a consonant, use 은; if a vowel, use 는.

사람은 / 남자는

의사는 / 학생은

집은 / 침대는

In Japanese, these particles are analogous to は.

To mark objects, the particles 을 and 를 are used. Similar rules apply as with topic markers: 을 after consonants; 를, vowels.

책을 / 차를

저는 핵을 read.

나는 차를 bought.

In Japanese, the を marks the objects.