לאן את אמורה לנסוע עכשיו, לבית המרקחת או למשרד?

Because לאן means to where? / where to?, so it asks about a destination.

• לאן את אמורה לנסוע? = Where are you supposed to go/travel?
• איפה את? = Where are you?

So לאן is used when someone is moving to a place, not just being located somewhere.

Here it is the pronoun you — specifically you addressed to one female.

In unpointed Hebrew, both are written את, but they are different words:

• אַתְּ / את = you (feminine singular), usually pronounced at
• אֶת / את = the direct-object marker, usually pronounced et

In this sentence, it clearly means you, because it is the subject of אמורה לנסוע.

In present-tense Hebrew, the verb to be is usually omitted.

So English you are supposed to travel becomes literally something like:

• את אמורה לנסוע
• you supposed to travel

That is completely normal Hebrew.
Hebrew usually leaves out am / is / are in the present tense.

אמורה means supposed to, expected to, or sometimes meant to, depending on context.

In this sentence:

• את אמורה לנסוע = you are supposed to travel/go

Grammatically, אמורה is the feminine singular form of אמור. It behaves like a participle/adjective and is followed by an infinitive:

• אמורה לנסוע = supposed to travel
• אמור לבוא = supposed to come
• אמורים לעבוד = supposed to work

It usually expresses expectation, plan, or obligation, but not as strongly as must.

Because the sentence is addressed to one female.

Hebrew marks gender in this kind of expression:

• את אמורה = you (female) are supposed to
• אתה אמור = you (male) are supposed to

So אמורה agrees with the feminine pronoun את.

Here are the main forms:

• לאן אתה אמור לנסוע עכשיו, לבית המרקחת או למשרד?
  Where are you supposed to go now... (to one male)

• לאן אתם אמורים לנסוע עכשיו, לבית המרקחת או למשרד?
  Where are you supposed to go now... (to a group, masculine or mixed)

• לאן אתן אמורות לנסוע עכשיו, לבית המרקחת או למשרד?
  Where are you supposed to go now... (to a group of females)

לנסוע usually means to travel, to go by vehicle, or to ride/drive somewhere.
ללכת literally means to walk, though in many contexts it can also mean to go in a general sense.

So:

• לנסוע suggests travel by car, bus, taxi, train, etc.
• ללכת can be used more generally, or literally for going on foot

In this sentence, לנסוע sounds natural if the person is expected to head to one of those places by some form of transport.

It is usually pronounced lin-SO-a.

A simple transliteration is:

• לנסוע = linsoa

The last part can feel unusual to English speakers because of the final ע, but in modern Israeli Hebrew the ע is often not strongly pronounced. Still, it affects the vowel pattern, so the word comes out roughly as lin-SO-a, not lin-so.

Hebrew word order is fairly flexible, especially with adverbs like עכשיו (now).

This sentence:

• לאן את אמורה לנסוע עכשיו...?

is very natural.

You could also hear:

• לאן את אמורה עכשיו לנסוע...?

Both are acceptable. The difference is mostly about rhythm and emphasis, not basic meaning.

Because ל־ often means to before a destination.

After verbs of motion like לנסוע (to travel/go), Hebrew commonly uses ל־:

• לנסוע למשרד = to go to the office
• לנסוע לבית המרקחת = to go to the pharmacy

You may also learn אל for to, but with everyday movement verbs, ל־ is extremely common and natural.

They do, because the two nouns are built differently.

1. למשרד

This is a simple noun with the definite article:

• המשרד = the office
• ל + המשרד → למשרד

So the ל combines with ה.

2. לבית המרקחת

This comes from a construct phrase:

• בית מרקחת = a pharmacy
• בית המרקחת = the pharmacy

In a construct phrase, the definiteness is usually marked on the second word, not the first. So the ה appears on המרקחת, not on בית.

Also, בית changes pronunciation in construct:

• בַּיִת = bayit = house
• בֵּית = beit = house of / בית־ in a compound

So:

• לבית המרקחת is pronounced roughly le-veit ha-merkachat

בית המרקחת is the normal Hebrew word for the pharmacy.

It is a fixed compound expression built like a construct phrase, similar to many other Hebrew nouns made of two words. Very roughly, it is something like house of the compound/ointment/medicine preparation historically, but you should treat it simply as the standard word for pharmacy.

A useful comparison is:

• בית ספר = school
• בית חולים = hospital
• בית מרקחת = pharmacy

So even though it is written as two words, together it functions as one idea.

A common transliteration is:

Le'an at amura linsoa akhshav, leveit ha-merkachat o la-misrad?

A rough stress guide:

• le-AN
• at a-mu-RA
• lin-SO-a
• akh-SHAV
• le-VEIT ha-mer-ka-CHAT
• o la-mis-RAD

That will get you quite close to natural modern pronunciation.