Это особо важно.

Because важно is the form normally used in the pattern Это важно = This is important.

Here, важно is not describing a masculine noun directly. It is being used predicatively, as part of the statement about это. In English, we also say This is important, not This is important one.

Compare:

• важный вопрос = an important question
• Это важно = This is important

So in Это особо важно, важно means important in the sense of is important.

Это here means this or sometimes it, depending on context.

It often refers to:

• a thing just mentioned
• a situation
• an idea
• something being pointed out

So Это особо важно can mean:

• This is especially important
• It is particularly important

Russian это is very common in this kind of sentence.

In this sentence, особо means especially, particularly, or especially so.

So:

• Это особо важно = This is especially important / This is particularly important

It adds emphasis, but not in exactly the same way as очень.

• очень важно = very important
• особо важно = especially / particularly important

So особо points more to special significance, not just a high degree.

This is a very common question, because all three can seem similar.

• очень = very
• особенно = especially
• особо = particularly / especially, often a bit more concise or stylistically marked

Examples:

• Это очень важно. = This is very important.
• Это особенно важно. = This is especially important.
• Это особо важно. = This is particularly important.

For many learners, особенно важно feels like the most neutral everyday way to say especially important.
Особо важно is also correct, but it can sound a little more formal, compact, or emphatic depending on context.

Because Russian usually omits the verb to be in the present tense.

So:

• Это важно literally looks like This important
• but it means This is important

This is completely normal in Russian.

Compare:

• Он дома. = He is at home.
• Она врач. = She is a doctor.
• Это особо важно. = This is especially important.

If the sentence were in the past or future, a form of to be would appear:

• Это было особо важно. = This was especially important.
• Это будет особо важно. = This will be especially important.

Особо is an adverb here.

It modifies важно, telling us how important something is:

• важно = important
• особо важно = particularly important

So the structure is:

• Это = subject-like element (this / it)
• особо = adverb
• важно = predicative adjective / predicate word

Yes, but the neutral order here is Это особо важно.

Russian word order is flexible, and changing it can shift emphasis.

For example:

• Это особо важно. = neutral, natural
• Особо важно это. = more emphasis on especially important
• Это важно особо. = possible in some contexts, but less natural here

For most learners, the safest choice is to keep:

Это особо важно.

If you want a very common alternative, Это особенно важно is also very natural.

Not exactly.

• Это очень важно = This is very important
• Это особо важно = This is especially / particularly important

The first emphasizes degree: it is highly important.
The second emphasizes special significance: it matters in a special way or in this particular case.

Sometimes both can work in translation, but the nuance is different.

A simple pronunciation guide is:

• Это — EH-tuh
• особо — uh-SOH-buh
• важно — VAHZH-nuh

Stress:

• Э́то
• осо́бо
• ва́жно

A more approximate full pronunciation:

EH-tuh uh-SOH-buh VAHZH-nuh

Notes:

• The жн in важно can be tricky. Say the ж like the s in measure, then go into n.
• Unstressed о often sounds closer to uh in actual speech.

Это особо важно is generally understandable and correct, but особо can sound a little more marked than очень or особенно.

Roughly speaking:

• Это очень важно — very common, neutral
• Это особенно важно — also very common, neutral
• Это особо важно — correct, but a bit more compact, pointed, or sometimes slightly formal depending on context

So a learner should recognize it easily, but might choose Это особенно важно first in everyday speech if they want the most neutral option.

Yes — very often.

In Russian, это can point to:

• an object: This
• a fact: This
• an action or situation: This / It

For example:

• Мы должны проверить документы. Это особо важно.
  = We need to check the documents. This is especially important.

Here это refers to the whole idea of checking the documents, not a single thing.

That is one reason Это важно is such a useful and common pattern in Russian.