התכולה נכנסת ליחידת האחסון.

Because the subject התכולה is grammatically feminine singular.

• תכולה is a feminine singular noun.
• In the present tense, Hebrew participle-like verb forms agree with the subject in gender and number.
• So with a feminine singular subject, you get נכנסת.
• If the subject were masculine singular, it would be נכנס.
• If it were feminine plural, it would be נכנסות.

So the agreement is:

• התכולה נכנסת
• not התכולה נכנס

התכולה means the contents or the content, depending on context.

A useful thing for English speakers to notice is that Hebrew often uses a singular noun where English prefers a plural expression.

So:

• תכולה = contents / capacity contents / what something contains
• התכולה = the contents

This word often appears in practical contexts such as:

• boxes
• containers
• storage
• packaging
• shipping
• room or closet contents

It is a more specific word than תוכן, which often means content in a more abstract sense, like the content of a book, speech, or website.

It can definitely mean both, depending on context.

Literally, נכנסת comes from the verb להיכנס, which means to enter / go in.

But in everyday Hebrew, להיכנס ל־ is also very commonly used for physical fit:

• זה לא נכנס לקופסה = it doesn’t fit into the box
• הכול נכנס לארון = everything fits in the closet

So in a sentence like התכולה נכנסת ליחידת האחסון, the intended sense is very often:

• the contents fit into the storage unit

rather than a dramatic literal enter.

Because this is a construct chain in Hebrew, called סמיכות.

The phrase is built like this:

• יחידת אחסון = storage unit
  literally: unit of storage

When the first noun is in construct state, it often changes form. Here:

• יחידה becomes יחידת

Then the preposition ל־ is attached:

• ליחידת האחסון = to/into the storage unit

So:

• יחידה = a unit
• יחידת אחסון = a storage unit
• יחידת האחסון = the storage unit
• ליחידת האחסון = to/into the storage unit

That is how definiteness works in a Hebrew construct chain.

In English, we say:

• the storage unit

In Hebrew, with a construct chain, the whole phrase becomes definite if the second noun is definite.

So:

• יחידת אחסון = a storage unit
• יחידת האחסון = the storage unit

Even though יחידת does not have ה־, the entire phrase is definite because האחסון is definite.

This is very normal Hebrew grammar.

Here ל־ means something like to, into, or in relation to entering/fitting into.

With the verb להיכנס, Hebrew commonly uses ל־:

• להיכנס לבית = to enter the house
• להיכנס לאוטו = to get into the car
• להיכנס לקופסה = to go into / fit into the box

So נכנסת ליחידת האחסון is the normal Hebrew pattern.

An English speaker might expect something closer to into, but Hebrew often uses ל־ where English uses into after motion verbs like this.

Yes. נכנסת here is the present-tense form of להיכנס for feminine singular.

Hebrew present tense is built from participle-like forms, so it can often mean:

• enters
• is entering
• goes in
• fits in

The exact English translation depends on context.

So התכולה נכנסת ליחידת האחסון could be understood as:

• the contents go into the storage unit
• the contents are going into the storage unit
• the contents fit into the storage unit

The dictionary form is להיכנס = to enter / to go in.

The present-tense forms are:

• נכנס — masculine singular
• נכנסת — feminine singular
• נכנסים — masculine plural
• נכנסות — feminine plural

So נכנסת is simply the feminine singular present form.

This verb belongs to the pattern נפעל in its dictionary form, which is why you see the נ־ at the beginning.

A simple pronunciation guide is:

ha-tkhulá nikhnéset le-yekhidát ha-ikhsún

A few notes:

• התכולה = ha-tkhulá
• נכנסת = nikhnéset
• ליחידת = le-yekhidát
• האחסון = ha-ikhsún

A more natural connected pronunciation may slightly smooth some sounds, but that guide is good for learners.

Because Hebrew is following the grammar of תכולה, which is singular.

In English, contents is plural, so we say:

• the contents fit

But Hebrew uses the singular noun תכולה, so the verb is singular too:

• התכולה נכנסת

This is a very common kind of mismatch between Hebrew and English: the two languages do not always package the same idea with the same number.

Yes, but the given order is the most neutral and standard:

• התכולה נכנסת ליחידת האחסון

This is basically:

• subject + verb + prepositional phrase

Hebrew can sometimes move parts around for emphasis, for example:

• ליחידת האחסון התכולה נכנסת

But that sounds marked or stylistic. For normal usage, the original sentence is the most straightforward form.