يسجل المشارك في ورشة العمل.

Because verb-first word order is very common in Modern Standard Arabic, especially in formal style.

So يسجل المشارك في ورشة العمل is a normal verb + subject + prepositional phrase sentence.

You can also say:

المشارك يسجل في ورشة العمل

That is also correct, but it uses a subject-first structure instead.

يسجل is the imperfect form of the verb سجّل.

Its fully vowelled form is:

يُسَجِّلُ

It is:

• 3rd person
• masculine
• singular

So it means something like he registers, he is registering, or sometimes he will register, depending on context.

The verb comes from the root س-ج-ل, which is connected with the idea of recording or registering.

In Arabic, the imperfect can cover several meanings that English separates more clearly.

So يسجل can mean:

• registers
• is registering
• sometimes will register

In this sentence by itself, the most natural reading is usually present or habitual.

If Arabic wants to make the future clearer, it can use:

• سيسجل
• سوف يسجل

Both mean will register.

In a verb-first sentence, the verb is normally singular when the subject comes after it.

Here the subject is المشارك and it is singular masculine, so يسجل is singular masculine too.

This pattern becomes especially noticeable with plural subjects. For example:

• يسجل المشاركون = The participants register

Even though المشاركون is plural, the verb often stays singular in formal verb-first Arabic.

If the sentence started with the subject instead, full agreement is expected:

• المشاركون يسجلون

So word order affects agreement.

Grammatically, المشارك means the participant because it has الـ.

But Arabic often uses the definite article in ways that do not match English exactly. Depending on context, المشارك can refer to:

• a specific participant already known in context, or
• a participant in a general, category-like sense

So even if English might sometimes say a participant, Arabic may still naturally use المشارك.

The word itself is the active participle of شارك and literally means the one participating / participant.

في usually means in, but with some verbs it is used where English would say in, for, or something similar.

With يسجل, Arabic often uses في to express enrolling or registering in an event, course, or activity:

• يسجل في الدورة = registers for the course
• يسجل في ورشة العمل = registers for the workshop

So you should not expect a one-to-one match between Arabic and English prepositions.

Because ورشة العمل is an iḍāfa construction, often called a construct phrase.

It is made of:

• ورشة = workshop
• العمل = work

Together, ورشة العمل literally means workshop of work, but idiomatically it means workshop.

In an iḍāfa:

• the first noun usually does not take الـ
• the second noun can take الـ
• if the second noun is definite, the whole phrase becomes definite

So:

• ورشة عمل = a workshop
• ورشة العمل = the workshop

That is why الورشة العمل is not correct here.

A fully vowelled version is:

يُسَجِّلُ المُشارِكُ في وَرْشَةِ العَمَلِ

Here is why:

• يُسَجِّلُ: the verb, ending in -u
• المشاركُ: the subject, so it is in the nominative
• في: a preposition
• ورشةِ: after a preposition, so it is genitive
• العملِ: also genitive, because it is the second part of the iḍāfa

In normal Arabic writing, these short vowels are usually omitted.

A careful pronunciation is:

yusajjilu al-mushāriku fī warshati al-ʿamali

A few helpful notes:

• يُسَجِّلُ has a doubled j sound because of the shadda on ج
• المشارك is al-mushārik
• ورشة is roughly war-sha
• الع in العمل contains the letter ع, which has no exact English equivalent

In connected speech, the sentence flows like:

yusajjilul-mushāriku fī warshatil-ʿamali

Yes. The verb سجّل can also mean record, write down, or document, depending on context.

For example:

• يسجل الملاحظات = he records/writes down the notes
• يسجل الصوت = he records the sound

So context is important.

In يسجل المشارك في ورشة العمل, the presence of في ورشة العمل strongly suggests the meaning registers for the workshop or enrolls in the workshop, not records.