Learn Hardcore Malay: Saya muat naik dokumen penting ke aplikasi itu sekarang. - I upload an important document to that app now.

In everyday Malaysian speech, Saya muat naik … is fine. In standard or formal Malay, prefer Saya memuat naik …. The active prefix meN- assimilates to the initial consonant: meN- + muat → memuat.

How do I say “I am uploading” (progressive) rather than a simple present?

Use sedang to mark an ongoing action: Saya sedang memuat naik dokumen penting …. You can also rely on time context: Saya memuat naik … sekarang. Using both together (e.g., “sedang … sekarang”) is usually redundant; pick one.

Where can I place “sekarang” in the sentence?

Flexible positions are natural:

Saya memuat naik … sekarang.
Sekarang saya memuat naik …
Saya sekarang memuat naik … All are acceptable, with only slight differences in emphasis.

Should it be ke, di, kepada, or ke dalam for “to the app”?

ke marks a destination: … ke aplikasi itu (to that app). Safe and standard for “upload to”.
di marks location (“on/at”): many people say … di aplikasi itu (uploaded on that app) in tech contexts; it’s common but less directional.
kepada is for recipients (people), not places: kepada Ali.
ke dalam (“into”) adds a sense of entering: … ke dalam aplikasi itu; optional and a bit heavier.
You can also combine: … ke akaun saya di aplikasi itu (to my account on that app).

Is “dokumen” singular or plural here? How do I specify number?

Malay doesn’t mark plural by default, so dokumen can be one or many. To be specific:

One: sebuah/satu dokumen penting
Some: beberapa dokumen penting
Many: banyak dokumen penting
Explicit plural (formal/emphasis): dokumen-dokumen penting

Do I need “yang” (dokumen yang penting) or is dokumen penting enough?

Dokumen penting is the normal “important document(s)”. Dokumen yang penting is more contrastive/restrictive (“the documents that are important” as opposed to others) or used when the adjective is expanded: dokumen yang sangat penting.

Is “ke aplikasi itu” natural, or should I name the app?

… ke aplikasi itu is fine if the app is already known from context. It’s often more idiomatic to name the platform: … ke Google Drive, … ke Instagram. For a formal tone referring back to a previously mentioned app, … ke aplikasi tersebut is common.

Is “aplikasi” the right word for “app”? What about perisian or platform?

aplikasi = app/application (mobile or desktop).
perisian = software (general term).
platform = platform/service (e.g., marketplace, social platform).
So your sentence’s aplikasi is the right choice for “app.”

Can I just use the English loanword “upload”?

Yes, in casual Malaysian usage you’ll hear Saya upload dokumen …. For standard/formal Malay, use (me)muat naik.

Why is “itu” after the noun (aplikasi itu), not before?

Malay demonstratives follow the noun:

aplikasi itu = that/the app
aplikasi ini = this app
A more formal “the aforementioned app” is aplikasi tersebut.

How do I say “upload it”? Do I need -kan?

Three safe options:

Name the object: Saya memuat naik dokumen itu.
Use the clitic pronoun with -kan on naik: Saya sudah memuat naikkannya (“I’ve uploaded it”). Here, naik + -kan + -nya → naikkannya, so the whole is memuat naikkannya.
Without -kan: Saya sudah memuat naiknya is widely used, though in some readings it can look like “its upload” (a nominalized form). Using … naikkannya avoids that ambiguity.

Can I switch the order to naik muat or split the verb?

No. Muat naik is a fixed compound verb. Don’t say naik muat, and don’t insert the object between them (avoid memuat dokumen naik). Attach suffixes to the second part if needed (e.g., naikkannya), or put the object after the whole verb phrase.

How would Indonesians say this?

Indonesian typically uses unggah: Saya (sedang) mengunggah dokumen penting ke aplikasi itu sekarang. In informal Indonesian, Saya upload dokumen penting ke aplikasi itu is also common.