يستلم العميل الرسالة.

Because verb–subject–object order is very common in Modern Standard Arabic.

So:

• يستلم = receives / is receiving
• العميل = the customer
• الرسالة = the message

This gives:

• يستلم العميل الرسالة = The customer receives the message

Arabic can also use subject–verb–object order:

• العميل يستلم الرسالة

That is also correct. In many contexts, the version starting with the verb sounds more neutral or more classically Arabic.

يستلم means he receives, he takes delivery of, or he accepts/collects, depending on context.

In this sentence, the most natural meaning is:

• receives

It is a present/imperfect tense verb, so it can also mean:

• receives
• is receiving
• sometimes will receive if the context points to the future

In Arabic, the verb itself already includes information about the subject.

يستلم by itself means:

• he receives

So Arabic does not need a separate word for he here.

Then العميل is added to specify who that he is:

• يستلم العميل = the customer receives

يستلم is a Form X verb from استلم.

Its basic dictionary form is:

• استلم = to receive / take delivery of

The present form is:

• يستلم = he receives

Learners often notice the pattern يستفعل in Form X present verbs. Here, the shape is:

• يستلم
• past: استلم
• verbal noun: استلام = receiving / receipt

The root is usually analyzed as:

• س ل م

This root is connected with ideas such as safety, peace, submission, and handing over/receiving in different verb forms.

In this sentence, the Form X verb استلم / يستلم has the meaning to receive or to take delivery of.

Because both nouns are definite.

• العميل = the customer
• الرسالة = the message

Without الـ, they would usually be indefinite:

• عميل = a customer
• رسالة = a message / letter

So the sentence specifically refers to:

• the customer
• the message

In this sentence:

• العميل is the subject = the one doing the action
• الرسالة is the object = the thing being received

You know this from a combination of:

1. Word order
   • After the verb, the first noun is often the subject.
2. Grammar/case
   • In fully vocalized Arabic:
     • العميلُ = nominative subject
     • الرسالةَ = accusative object

So the fully vocalized sentence is:

• يستلمُ العميلُ الرسالةَ

Because everyday Arabic writing usually leaves out short vowels and most case endings.

So you often see:

• يستلم العميل الرسالة

But in full grammatical spelling, it would be:

• يستلمُ العميلُ الرسالةَ

Those endings tell you:

• ـُ on العميلُ = subject
• ـَ on الرسالةَ = object

In normal printed Arabic, readers usually understand this from context even without the endings.

Here the ل of الـ is not pronounced normally, because ر is a sun letter.

So:

• written: الرسالة
• pronounced: ar-risālah (or with case ending: ar-risālata)

By contrast, in العميل, the ع is a moon letter, so the ل is pronounced:

• al-ʿamīl

So the whole sentence is pronounced approximately:

• yastalimu al-ʿamīlu ar-risālata

Yes.

The Arabic imperfect/present tense often covers several English meanings, depending on context:

• receives
• is receiving
• sometimes will receive

So يستلم العميل الرسالة could mean:

• The customer receives the message
• The customer is receiving the message

If you want to make the progressive idea clearer, Arabic often relies on context or extra words rather than a special verb form like English is receiving.

Yes, absolutely.

Both are correct:

• يستلم العميل الرسالة
• العميل يستلم الرسالة

The difference is mainly in style and focus:

• يستلم العميل الرسالة: starts with the action; very natural in MSA
• العميل يستلم الرسالة: starts with the subject; can feel a bit more like The customer, he receives the message

Both are common and understandable.

العميل most commonly means:

• the customer
• the client

Which English word fits best depends on context:

• in a store: customer
• in business/services: client

So this sentence could also be understood as:

• The client receives the message

if the context is professional rather than commercial.

Then both the noun and the verb would change:

• تستلم العميلة الرسالة

This means:

• The female customer receives the message

Changes:

• يستلم → تستلم for a feminine singular subject
• العميل → العميلة

So Arabic marks gender more clearly than English does.

Yes. رسالة can mean:

• message
• letter
• sometimes epistle in more formal contexts

So the sentence could mean either:

• The customer receives the message
• The customer receives the letter

The correct translation depends on context. In modern everyday usage, message is often a good choice, but letter is also possible.