Learn French: J'aimerais une carte d'identité. - I would like an identity card.

J'aimerais is in the conditional tense, which is used for polite requests and translates to "would like". You might be thinking of the imperfect tense (used for past habits), which is j'aimais (I used to like). Notice the extra r in j'aimerais—that r sound before the ending is the signature of the conditional and future tenses!

Can I say je voudrais instead of j'aimerais here?

Yes, absolutely! Both j'aimerais (from aimer) and je voudrais (from vouloir) are extremely common, polite ways to say "I would like" in French. They are practically interchangeable when making a polite request or stating a wish at a counter or in a restaurant.

How is the conditional form j'aimerais built?

To form the conditional for polite requests, you generally take the full infinitive of the verb (in this case, aimer) and add the imperfect endings. For je, the ending is -ais. Put them together, and you get aimerais!

Why is it carte d'identité instead of carte de l'identité?