Nu trimite documentul fără să citești formularul încă o dată.

Because this is a negative command addressed to one person informally.

• trimiți = you send / you are sending (present indicative)
• trimite! = send! (imperative)
• nu trimite! = don’t send! (negative imperative)

So Nu trimite documentul... means Don’t send the document..., not You don’t send the document...

A useful comparison:

• Trimiți documentul. = You send the document.
• Trimite documentul! = Send the document!
• Nu trimite documentul! = Don’t send the document!

Yes. In this sentence, trimite is the 2nd person singular imperative of a trimite.

The sentence is talking to one person in an informal you sense:

• Trimite! = Send!
• Nu trimite! = Don’t send!

If you were talking to several people, or using the polite/formal form, you would say:

• Nu trimiteți documentul... = Don’t send the document...

Romanian usually doesn’t need a subject pronoun when the verb ending already shows who the subject is.

Here:

• trimite shows an imperative to you (singular)
• citești shows you read

So Romanian can leave out tu.

You could add tu for emphasis, but normally you would not:

• Tu nu trimite documentul... sounds marked/emphatic, not the most neutral version.

The natural Romanian sentence simply leaves you understood.

fără să means without followed by a verb, so here it means without reading.

Romanian often uses fără să + subjunctive where English uses without + -ing.

So:

• fără să citești = without reading
• literally: without that you read

This is a very common structure:

• A plecat fără să spună nimic. = He left without saying anything.
• Nu intra fără să bați la ușă. = Don’t come in without knocking on the door.

So in your sentence:

• Nu trimite documentul fără să citești formularul...
• Don’t send the document without reading the form...

Yes, it is subjunctive, because it comes after să.

In Romanian, the present subjunctive is usually formed with să + verb, and for many verbs the actual verb form looks the same as the present indicative.

So:

• tu citești = you read / you are reading
• să citești = that you read / for you to read / to read

In this sentence, să is what signals the subjunctive:

• fără să citești = without reading

So even though citești looks familiar, the presence of să changes the grammar.

Because Romanian attaches the definite article to the end of the noun.

So:

• document = a document
• documentul = the document

and

• formular = a form
• formularul = the form

This is one of the big differences from English. Instead of putting the before the noun, Romanian usually adds it as an ending:

• carte = book
• cartea = the book
• băiat = boy
• băiatul = the boy

So:

• documentul = the document
• formularul = the form

Yes, they are normally understood as different things.

• documentul = the document
• formularul = the form

The idea is probably: Don’t send the document without reading the form one more time.

Maybe the form contains information you need to check before sending the document.

A learner might expect the same noun twice, but Romanian is doing exactly what English can do too: mention one item, then another related item.

încă o dată means once more, one more time, or simply again.

In this sentence:

• citești formularul încă o dată
• read the form one more time

Literally:

• încă = still / yet / another
• o dată = one time

Together, încă o dată often means again / once again.

Examples:

• Spune încă o dată. = Say it again.
• Citește încă o dată. = Read it one more time.

Yes, often you could.

• încă o dată = one more time / once again
• din nou = again / anew

In many contexts they are both natural:

• Citește formularul încă o dată.
• Citește formularul din nou.

A small nuance:

• încă o dată often emphasizes one additional repetition
• din nou is a more general again

So in this sentence, încă o dată fits very well because it suggests checking the form one more time before sending.

Because the normal word order places încă o dată after the verb phrase or after the object phrase, not right after să.

Natural:

• fără să citești formularul încă o dată
• fără să citești încă o dată formularul

The first version is especially natural and neutral.

Less natural:

• fără să încă o dată citești formularul

That order sounds awkward in standard Romanian.

So if you want to say without reading the form one more time, keep încă o dată later in the clause.

Word-for-word, Romanian may look a bit like that because of fără să, but that is not how good English should translate it.

A more natural English translation is:

• Don’t send the document without reading the form again.
• Don’t send the document without reading the form one more time.

So this is a case where the Romanian grammar and the English grammar are different:

• Romanian: fără să + verb
• English: without + -ing

You would change the verb forms to 2nd person plural, which is also used for the polite singular you.

So:

• informal singular: Nu trimite documentul fără să citești formularul încă o dată.
• plural or formal: Nu trimiteți documentul fără să citiți formularul încă o dată.

Changes:

• trimite → trimiteți
• citești → citiți

This is a very useful pattern in Romanian:

• tu: citești
• voi / dumneavoastră: citiți

It is informal singular, because it uses the singular command and singular you form:

• Nu trimite
• citești

The tone itself is fairly neutral/practical, but grammatically it is addressed to someone you say tu to.

If you wanted a more formal version, you would say:

• Nu trimiteți documentul fără să citiți formularul încă o dată.

That would work for:

• one person formally (dumneavoastră)
• several people (voi / dumneavoastră)