Υποβάλλεται φάκελος δικαιολογητικών υπό την προϋπόθεση ότι είναι έτοιμος.

Υποβάλλεται is the 3rd person singular present middle/passive form of υποβάλλω.

In this sentence, it is used with a passive meaning: is submitted.

This is very common in formal or administrative Greek. Instead of saying who submits the documents, Greek often focuses on the procedure itself:

• Υποβάλλεται φάκελος... = A dossier/file is submitted...
• In more natural English, this often corresponds to A dossier must be submitted... or You submit a dossier...

So the passive here is not strange; it is a standard official-style way to describe requirements.

Because in the passive sentence, φάκελος is the grammatical subject.

Compare:

• Active: Ο αιτών υποβάλλει φάκελο. = The applicant submits a dossier.
• Passive: Υποβάλλεται φάκελος. = A dossier is submitted.

In the active version, φάκελο is the object, so it is accusative.
In the passive version, that same idea becomes the subject, so it changes to nominative: φάκελος.

Δικαιολογητικών is the genitive plural of δικαιολογητικό, which means supporting document, required document, or justification paper, depending on context.

So:

• φάκελος = file, folder, dossier
• δικαιολογητικών = of supporting documents

Together, φάκελος δικαιολογητικών means something like:

• a dossier of supporting documents
• a file containing the required documents

Greek often uses the genitive after a noun like φάκελος to show contents or association, just like English uses of.

Because this is typical official or bureaucratic style.

In administrative Greek, nouns are often left without an article when the text is stating a rule, requirement, or procedure in a general way:

• Υποβάλλεται φάκελος δικαιολογητικών.

This sounds like a regulation or instruction: A dossier of supporting documents is submitted / must be submitted.

If you added an article, for example ο φάκελος δικαιολογητικών, it would sound more specific, as if you were referring to a particular dossier already known in the context.

So the absence of the article makes the statement more general and procedural.

Yes, it is quite formal.

Υπό την προϋπόθεση ότι means:

• on the condition that
• provided that
• under the condition that

This is the kind of phrase you often see in laws, regulations, applications, and official instructions.

A less formal or more everyday alternative might be:

• με την προϋπόθεση ότι
• sometimes simply αν, depending on the context

So this phrase is correct, but definitely belongs to a more formal register.

Because ότι and ό,τι are different words.

• ότι = that
• ό,τι = whatever / anything that

In this sentence, υπό την προϋπόθεση ότι... means under the condition that..., so the correct form is ότι.

Examples:

• Ξέρω ότι έρχεται. = I know that he is coming.
• Πάρε ό,τι θέλεις. = Take whatever you want.

So here, ότι is the conjunction that, not the pronoun whatever.

Because έτοιμος agrees with φάκελος.

Φάκελος is:

• masculine
• singular
• nominative

So the adjective must also be:

• masculine
• singular
• nominative

That gives έτοιμος.

Compare:

• ο φάκελος είναι έτοιμος = the dossier is ready
• το έγγραφο είναι έτοιμο = the document is ready
• τα δικαιολογητικά είναι έτοιμα = the supporting documents are ready

So the grammar shows that έτοιμος refers to φάκελος, not to δικαιολογητικά.

Grammatically, it refers to φάκελος.

That is because:

• φάκελος is masculine singular
• έτοιμος is also masculine singular

So the sentence is saying that the file/dossier is ready.

In practical terms, in this kind of context, ready often means something like:

• prepared
• complete
• assembled
• ready for submission

So even though the literal meaning is ready, the intended practical meaning may be closer to properly prepared or complete.

Not necessarily.

In formal Greek, especially in instructions, regulations, and administrative language, the present tense is often used to describe what is generally required or what the procedure is.

So:

• Υποβάλλεται φάκελος δικαιολογητικών...

does not have to mean that the submission is happening right now. It can mean:

• A dossier is submitted
• A dossier must be submitted
• One submits a dossier

This is similar to the way English sometimes uses the present in formal instructions, but Greek does it very often in bureaucratic writing.

Probably not in ordinary conversation.

The sentence is grammatically fine, but it sounds official and bureaucratic. In everyday speech, a speaker would often use something more direct, for example with an active verb or a simpler structure.

For example, conversational Greek might prefer something more like:

• Πρέπει να υποβάλεις φάκελο δικαιολογητικών...
• Υποβάλλεις τον φάκελο δικαιολογητικών αν είναι έτοιμος.

The original sentence is the kind of phrasing you expect in forms, announcements, regulations, or institutional instructions.