Prepaid ang mobile plan na ito.

Because Filipino often uses a predicate-first word order.

So instead of the English-style order:

• This mobile plan is prepaid

Filipino commonly says:

• Prepaid ang mobile plan na ito

A useful pattern to notice is:

• Predicate + ang + topic

Here:

• Prepaid = the description
• ang mobile plan na ito = the thing being described

This is very normal in Filipino.

Not exactly. Ang is not simply the Filipino word for the.

In this sentence, ang marks the topic or the noun phrase being focused on in the sentence. It tells you that mobile plan na ito is the main thing being identified or described.

So in:

• Prepaid ang mobile plan na ito

ang marks:

• mobile plan na ito = the topic / subject-like part

English learners often first think of ang as the, but that can be misleading. Sometimes it overlaps with the, but its real job is grammatical marking, not just definiteness.

Na is a linker. Filipino uses linkers to connect words smoothly inside a phrase.

Here, na links:

• mobile plan
  • ito

So:

• mobile plan na ito = this mobile plan

The linker is required because ito is modifying or identifying mobile plan.

A very important pattern is:

• if the first word ends in a consonant, use na
• if the first word ends in a vowel or n, you often use -ng

Examples:

• plan na ito
• batang ito
• teleponong ito

Both patterns are possible.

You can say:

• mobile plan na ito
• itong mobile plan

Both mean this mobile plan.

The difference is mainly in structure:

• mobile plan na ito = noun first, then demonstrative
• itong mobile plan = demonstrative first, then noun

So your sentence could also be rephrased as:

• Prepaid itong mobile plan

That is also natural.

Yes. In this sentence, prepaid functions as a descriptive word for the mobile plan, similar to an adjective in English.

Filipino often uses borrowed English words this way, especially for technology, business, and telecom terms.

So in:

• Prepaid ang mobile plan na ito

prepaid is the property or classification being assigned to the plan.

You can think of it as:

• This mobile plan is prepaid
• The status/type of this mobile plan is prepaid

Yes. That is also correct.

Compare:

• Prepaid ang mobile plan na ito
• Ang mobile plan na ito ay prepaid

Both mean the same thing.

The version with ay is more like an inverted or more formal subject-first structure. It can sound a bit more careful, formal, or written, while the predicate-first version is very common in everyday Filipino.

So:

• Prepaid ang mobile plan na ito = very normal
• Ang mobile plan na ito ay prepaid = also correct, slightly more formal or more explicitly structured

It is understandable, and borrowing English terms is very common in Filipino, especially for modern topics like phones, data, and telecom services.

That said, in real conversation, many speakers might shorten or adjust it, for example:

• plan na ito
• cellphone plan na ito
• plan ng phone na ito

So mobile plan is not wrong, but actual usage may vary depending on the speaker and context.

The most important grammar point in your sentence is still the Filipino structure:

• Prepaid + ang + noun phrase

Some very natural casual alternatives are:

• Prepaid ang plan na ito.
• Prepaid itong plan.
• Prepaid ito.
  if the context already makes it clear you are talking about the mobile plan

These are shorter and sound very conversational.

Your original sentence is still fine, but learners should know that Filipino often prefers shorter phrasing in everyday speech, especially when the context is already clear.