zairyuukaado to mainanbaakaado wo miseru.

Here, と means and.

So:

• 在留カード と マイナンバーカード = a residence card and a My Number card

In this sentence, と connects two nouns in a complete list. It sounds like both items are included.

Because the two nouns are being treated as one combined object:

• 在留カード と マイナンバーカード を 見せる

This means show the residence card and the My Number card.

Japanese often puts the object marker を only once, after the whole noun phrase, instead of after each noun.

So this is natural:

• A と B を 見せる

Not usually:

• A を B を 見せる

見せる means to show.

It is related to 見る, which means to see / to look at.

• 見る = to see
• 見せる = to show

You can think of 見せる as something like to make someone see. So:

• カードを見る = to look at a card
• カードを見せる = to show a card

That is why 見せる is the correct verb here, not 見る.

It is in the dictionary form (plain form).

That form can mean things like:

• show
• will show
• to show (when listed as a vocabulary item)

Without more context, 見せる is just a plain statement form. In isolation, it may sound like:

• I show / will show
• someone shows / will show

depending on context.

In textbooks and vocabulary lists, dictionary form is the basic form used to introduce verbs.

The sentence does not say explicitly.

Japanese often leaves out information that is understood from context, especially:

• the subject
• the listener
• the person receiving the action

So 在留カード と マイナンバーカード を 見せる。 could mean:

• I show my residence card and My Number card
• You show your residence card and My Number card
• Please show the residence card and My Number card
• (Someone) shows the residence card and My Number card

The exact meaning depends on the situation.

No, normal Japanese usually does not use spaces like this.

A more natural written version would be:

• 在留カードとマイナンバーカードを見せる。

Spaces are often added in learning materials to make the sentence easier to read.

They are read:

• 在留カード → ざいりゅうカード
• マイナンバーカード → マイナンバーカード

A useful point here is that カード is a loanword written in katakana, while 在留 is written in kanji.

So 在留カード is a mixed-script word: kanji + katakana.

Because カード is a loanword from English card.

In Japanese:

• kanji are often used for words of Chinese origin or core vocabulary
• hiragana is used for grammar endings and native words
• katakana is often used for foreign loanwords

So in 在留カード and マイナンバーカード, カード is in katakana because it is a borrowed word.

Not always, but in this sentence it is very close to and.

Here, A と B gives a clear, complete list of items. It suggests A and B, specifically those two.

That is slightly different from a particle like や, which can give a more partial, example-like list:

• A と B = A and B
• A や B = A, B, and possibly other things

So と is a very natural choice here if both cards are required.

No, this is the plain form, not the polite form.

• 見せる = plain
• 見せます = polite

So a polite version would be:

• 在留カードとマイナンバーカードを見せます。

And if you wanted to ask someone politely to show them, you might say:

• 在留カードとマイナンバーカードを見せてください。

So the original sentence sounds more like a plain statement, a dictionary example, or an instruction title rather than polite spoken conversation.

Yes, that is a very natural understanding.

Because A と B を 見せる includes both nouns in one object phrase, it strongly suggests showing both items:

• the residence card
• the My Number card

So show both cards is a good natural-English way to understand it.

Yes, but the original version is more compact and natural.

For example, you could say:

• 在留カードを見せる。マイナンバーカードを見せる。

That means:

• Show the residence card. Show the My Number card.

But if you want one sentence with both objects together, Japanese normally uses:

• 在留カードとマイナンバーカードを見せる。

That is smoother and more natural.

Because the person receiving the action is simply omitted.

With 見せる, you can mention the person you show something to:

• 先生にカードを見せる = show the card to the teacher

But if the listener already knows who the card is being shown to, Japanese often leaves that out.

So this sentence is just focusing on what is shown, not to whom it is shown.