صديقتي كتبت عنوانها ورقم هاتفها على هذه الصفحة.

صديقتي is made of:

• صديقة = a female friend
• ـي = my

So صديقتي means my female friend.

This is specifically feminine. If the friend were male, you would say صديقي.

A useful spelling note: when a noun ending in ة takes a suffix like ـي, that ة changes to ت in writing, so صديقة becomes صديقتي.

Because the subject is feminine singular: صديقتي.

• كتب = he wrote
• كتبت = she wrote

So the ـت on كتبت marks the verb as third-person feminine singular in the past tense.

In Arabic, the verb itself often already tells you the subject.

كتبت already means she wrote, so you do not need to add a separate pronoun like هي.

You could say هي كتبت in some contexts, but it would usually add emphasis or contrast. In a normal sentence, just كتبت is enough.

Arabic allows more than one common word order.

This sentence uses subject + verb order:

• صديقتي كتبت... = My friend wrote...

You could also say:

• كتبت صديقتي...

Both are possible in MSA. Starting with صديقتي can feel a bit more like you are introducing or emphasizing my friend.

The suffix ـها means her.

So:

• عنوانها = her address
• هاتفها = her phone

Arabic often uses attached pronoun suffixes instead of separate words like her, his, my, and so on.

Some common ones are:

• ـي = my
• ـه = his
• ـها = her

This is an iḍāfa construction, often called a genitive or possession construction.

It is literally:

• رقم = number
• هاتفها = her phone

So together:

• رقم هاتفها = her phone number

Arabic very often expresses ideas like phone number, school door, city center, etc. through this noun-to-noun structure.

Important rule: in an iḍāfa, the first noun usually does not take الـ.

That is why you get رقم هاتفها, not الرقم الهاتفها.

Because رقم is the first word in an iḍāfa construction: رقم هاتفها.

In an iḍāfa:

• the first noun does not take الـ
• the whole phrase becomes definite if the second part is definite

Here, هاتفها is definite because of ـها (her), so the whole phrase رقم هاتفها is definite: her phone number.

Because صفحة is a feminine noun.

For singular nouns:

• هذا = this (masculine)
• هذه = this (feminine)

So:

• هذه الصفحة = this page

Since صفحة is feminine, the demonstrative must also be feminine.

على means on or upon.

So على هذه الصفحة means on this page.

This is the normal preposition to use for writing something on a surface, including paper or a page.

Also, after a preposition like على, the following noun phrase is grammatically in the genitive case, even though short vowels are usually not written in everyday Arabic text.

A fully vocalized version would be:

صديقتي كتبتْ عنوانَها ورقمَ هاتفِها على هذه الصفحةِ.

Here is what is happening:

• صديقتي: the subject
• كتبتْ: past tense verb, she wrote
• عنوانَها: direct object, so accusative
• رقمَ: also part of the direct object phrase, so accusative
• هاتفِها: second term of the iḍāfa, so genitive
• الصفحةِ: after على, so genitive

In normal printed Arabic, these endings are usually omitted, but they still exist grammatically.

Arabic usually makes the possession clear for each item.

So:

• عنوانها = her address
• رقم هاتفها = her phone number

Repeating the possessive marking helps avoid ambiguity and sounds natural. English also often repeats possession in similar cases: her address and her phone number, even if English can sometimes shorten it.

In Arabic, especially for learners, it is safest to mark each possessed expression clearly the way this sentence does.