i bolpeneun jal nawaseo hoeui memohal ttae pyeonhae.

Here, 나오다 is being used in a very common extended sense.

With pens, pencils, markers, ink, water, sound, and similar things, 나오다 can mean to come out / to flow / to work properly.

So:

• 이 볼펜은 잘 나와요 = This pen writes well / the ink comes out well
• 잉크가 안 나와요 = The ink isn’t coming out
• 물이 잘 나와요 = The water comes out well

In 잘 나와서:

• 잘 = well
• 나오다 = to come out / write properly
• -아서/어서 = because / so

So 잘 나와서 means something like because it writes smoothly or because the ink comes out well.

은 is the topic marker. It marks 이 볼펜 as the topic of the sentence: as for this pen...

So the sentence has the feel of:

• As for this pen, it writes well, so it’s convenient when taking meeting notes.

Using 은 is very natural here because the speaker is making a comment about this pen in general.

If you used 이 볼펜이, it would sound more like you are identifying the pen itself or emphasizing that this pen is the one that writes well, often in contrast with something else.

Very roughly:

• 이 볼펜은... = speaking about this pen as a topic
• 이 볼펜이... = emphasizing that this pen is the one that does the action/state

This is a good question because learners often expect an object particle.

Here, 회의 메모 works like a noun phrase meaning meeting notes or notes from a meeting.

So 회의 메모하다 is understood as to take meeting notes.

You can think of it like:

• 회의 메모 = meeting memo / meeting notes
• 회의 메모하다 = to make/take meeting notes

Korean often allows this kind of noun + noun combination without a particle, especially in compact everyday expressions.

A more expanded version could be:

• 회의 내용을 메모할 때 = when taking notes on the meeting content
• 회의를 메모할 때 is less natural for this meaning

So 회의 메모할 때 is a natural, compressed way to say when taking meeting notes during a meeting.

메모할 때 is made from:

• 메모하다 = to take notes / to make a memo
• 메모할 = future/attributive form modifying a noun
• 때 = time / when

So literally:

• 메모할 때 = the time when one takes notes → when taking notes

This pattern is very common:

• 먹을 때 = when eating
• 갈 때 = when going
• 공부할 때 = when studying

With action verbs, the -ㄹ/을 때 form usually means when doing or when about to do, depending on context. Here it simply means when taking notes.

편해 is the informal, casual present-tense form of 편하다.

So:

• 편하다 = dictionary form
• 편해요 = polite speech
• 편해 = casual speech

This means the sentence is in a casual style, probably said to a friend, coworker, or in relaxed conversation.

Compare:

• 이 볼펜은 잘 나와서 회의 메모할 때 편해.
  casual
• 이 볼펜은 잘 나와서 회의 메모할 때 편해요.
  polite
• 이 볼펜은 잘 나와서 회의 메모할 때 편합니다.
  formal

Yes, but in Korean 편하다 is broader than English comfortable.

It can mean:

• comfortable
• convenient
• easy to use
• handy

In this sentence, 편해 is best understood as:

• It’s convenient
• It’s easy to use
• It makes note-taking easier

Because the subject is a pen, convenient or handy sounds more natural in English than comfortable, even though 편하다 is the Korean word being used.

Here it most naturally gives a reason:

• It writes well, so / because of that, it’s convenient when taking meeting notes.

The ending -아서/어서 often connects two clauses with a cause-and-result relationship.

So:

• 잘 나와서 편해 = It writes well, so it’s convenient

In some contexts -아서/어서 can feel more like simple connection, but in this sentence the causal reading is the natural one.

Yes. Adding 는 after 때 changes the nuance a bit.

• 메모할 때 편해 = it’s convenient when taking notes
• 메모할 때는 편해 = it’s convenient at least when taking notes / as for when taking notes, it’s convenient

The 는 adds contrast or topic emphasis. It can imply something like:

• maybe it is especially convenient in that situation
• maybe in other situations, the speaker is not making the same claim

So the original sentence without 는 is a plain, neutral statement. Adding 는 would make it a little more contrastive.

Yes, it is natural conversational Korean.

A native speaker might also say similar things like:

• 이 볼펜은 잘 써져서 회의 메모할 때 편해.
• 이 볼펜은 필기가 잘 돼서 회의 메모할 때 편해.
• 이 볼펜은 잉크가 잘 나와서 메모하기 편해.

Each version shifts the wording a little:

• 잘 나와서 focuses on the ink coming out well
• 잘 써져서 focuses on the pen writing smoothly
• 필기가 잘 돼서 focuses on writing performance
• 메모하기 편해 means it’s convenient for taking notes

But your original sentence is perfectly natural and easy to understand.

The understood subject is the pen, or more loosely using this pen.

Korean often leaves out subjects when they are obvious from context.

So the sentence can be understood as:

• This pen writes well, so it’s convenient when taking meeting notes.
• or Using this pen is convenient when taking meeting notes.

Korean does not always need to spell that out. Once 이 볼펜은 is introduced as the topic, the rest of the sentence naturally describes that pen.

No, it is very common and natural with pens.

When talking about a pen, 잘 나오다 usually implies:

• the ink flows smoothly
• the pen is not scratchy
• the writing appears clearly
• the pen is working properly

So if you say:

• 이 볼펜 잘 안 나와.

that means:

• This pen isn’t writing well
• The ink isn’t coming out properly

This is one of the standard expressions Koreans use for pens, so it is worth memorizing as a chunk.