Mi petas, ke vi skribu vian adreson kaj telefonnumeron ĉi tie.

Because after Mi petas, ke... Esperanto normally uses the -u verb form.

Here, skribu means something like write in the sense of a request or instruction, not a statement of fact.

• skribas = writes / is writing
• skribi = to write
• skribu = write / should write / please write

So:

• Mi petas, ke vi skribu... = I ask that you write...

This is a very common pattern:

• Mi volas, ke vi venu. = I want you to come.
• Ŝi petis, ke mi atendu. = She asked me to wait.

Ke means that and introduces a subordinate clause.

So the sentence is structured like this:

• Mi petas = I ask
• ke vi skribu vian adreson kaj telefonnumeron ĉi tie = that you write your address and telephone number here

In English, that is often omitted:

• I ask that you write...
• I ask you to write...

In Esperanto, ke is not usually omitted in this pattern.

The -n ending marks the direct object.

The person is being asked to write what?

• vian adreson
• telefonnumeron

Those are the things being written, so they take -n.

Also, vian gets -n because adjectives and possessive words agree with the noun they describe:

• via adreso = your address
• vian adreson = your address as a direct object

So:

• vian adreson
• telefonnumeron

Both nouns are objects, so both have -n.

Yes. Vian can apply to both nouns.

So:

• vian adreson kaj telefonnumeron

means:

• your address and telephone number

Esperanto often avoids repeating words when the meaning is clear. If you wanted extra emphasis or clarity, you could also say:

• vian adreson kaj vian telefonnumeron

But in normal usage, the shorter version is completely fine.

Yes. Esperanto commonly forms compound words by combining roots into a single word.

Here:

• telefon- = telephone
• numero = number

So:

• telefonnumero = telephone number

In the sentence it becomes telefonnumeron because of the direct object -n.

Notice the double n:

• one n belongs to the compound itself: telefonnumero
• the final -n is the accusative ending: telefonnumeron

That is completely normal in Esperanto.

It can feel slightly unusual if you translate it word for word as I ask. But in Esperanto, Mi petas is a normal and natural way to make a polite request.

So this sentence is not awkward in Esperanto.

Depending on context, English might translate it as:

• I ask that you write your address and telephone number here.
• Please write your address and telephone number here.
• I would like you to write your address and telephone number here.

The exact English wording depends on tone, but Mi petas is a standard polite expression.

Yes. That is another common way to say it.

Compare:

• Mi petas, ke vi skribu vian adreson...
• Mi petas vin skribi vian adreson...

Both are natural and mean roughly the same thing.

The first uses:

• ke + -u

The second uses:

• a direct object person (vin) + infinitive (skribi)

Both are common in Esperanto. A learner should recognize both patterns.

Esperanto normally uses vi for both singular and plural, and for both informal and polite situations.

So vi can mean:

• you (one person)
• you (more than one person)

There is an older form ci, but it is very rare in normal modern Esperanto. In everyday use, just use vi.

So in this sentence, vi is exactly what you would expect.

Ĉi tie means here.

It is made from:

• tie = there
• ĉi = a particle that brings the meaning close to the speaker

So:

• tie = there
• ĉi tie or tie ĉi = here

Both ĉi tie and tie ĉi are correct. Ĉi tie is probably more common in many contexts.

Yes, Esperanto word order is fairly flexible, but this version is the most straightforward and natural.

The standard order here is:

• Mi petas
• ke vi skribu
• vian adreson kaj telefonnumeron
• ĉi tie

You could move ĉi tie earlier for emphasis:

• Mi petas, ke vi ĉi tie skribu vian adreson kaj telefonnumeron.

But that sounds more marked. For normal use, the original sentence is best.

Yes. Petas is present tense.

• Mi petas = I am asking / I ask

The main verb is in the present because the speaker is making the request now.

Then the subordinate verb is in the -u form:

• skribu

So the sentence combines:

• a present-tense main verb: petas
• a volitive/request form in the subordinate clause: skribu

That combination is completely normal.

A few parts may be new for an English speaker:

• ĉ sounds like ch in church
• skr in skribu is pronounced fully; don’t insert an extra vowel
• u sounds like oo in food
• every vowel is pronounced clearly

So roughly:

• ĉi ≈ chee
• tie ≈ TEE-eh
• skribu ≈ SKREE-boo

And remember that Esperanto stress is on the second-to-last syllable:

• pe-TAS
• skri-BU
• a-DRE-son
• te-le-fon-nu-ME-ron

Not exactly, but it often functions similarly in polite requests.

Literally, Mi petas means I ask or I request. In context, though, it may be translated more naturally as please.

For example:

• Mi petas, ke vi atendu. = Please wait. / I ask that you wait.
• Mi petas pardonon. = I beg pardon.

So it does not equal please word-for-word, but it can serve a similar polite function in many sentences.