Η μορφή είναι απλή.

Η is the definite article for a feminine singular noun in the nominative case.
Here it means the.

So:

• η μορφή = the form / the shape

A very important detail: Η here is the article, not the pronoun she. In this sentence, it clearly functions as the because it comes directly before the noun μορφή.

In Greek, every noun has a grammatical gender: masculine, feminine, or neuter.
μορφή is simply a feminine noun, so it takes:

• the feminine article η
• the feminine form of the adjective, απλή

This is grammatical gender, so it does not mean the form itself is biologically female. It just means the noun belongs to the feminine class.

Because adjectives in Greek must agree with the noun they describe in:

• gender
• number
• case

Since μορφή is:

• feminine
• singular
• nominative

the adjective must also be feminine singular nominative:

• masculine: απλός
• feminine: απλή
• neuter: απλό

So:

• Η μορφή είναι απλή. = The form is simple.

είναι means is (or are, depending on the sentence). It is the present tense form of the verb to be.

In this sentence:

• Η μορφή = the subject
• είναι = is
• απλή = simple

So the structure is very similar to English:

• The form is simple.

In this sentence, yes, it matches English quite closely:

• Η μορφή = subject
• είναι = verb
• απλή = adjective

So it follows a normal subject + verb + complement pattern.

However, Greek word order is often more flexible than English. For emphasis, you may also see things like:

• Απλή είναι η μορφή.

That still means essentially The form is simple, but with different emphasis.

A natural pronunciation is approximately:

• i mor-FEE EE-ne a-PLEE

A few notes:

• Η is pronounced ee
• μορφή has the stress on the last syllable: mor-FEE
• είναι is usually pronounced EE-ne
• απλή has the stress on the last syllable: a-PLEE

So the whole sentence sounds roughly like:

• ee mor-FEE EE-ne a-PLEE

Greek uses the accent mark to show which syllable is stressed.

In this sentence:

• μορφή → stress on -φή
• είναι → stress on εί-
• απλή → stress on -πλή

Stress is important in Greek pronunciation, and accent marks are normally written in standard spelling.

Note that the article Η does not have an accent here.

The key words are in the nominative case.

• η μορφή = nominative singular
• απλή = nominative singular feminine, agreeing with μορφή

This is because μορφή is the subject of the sentence, and the adjective describing it matches it.

The verb είναι does not change that; the adjective after to be still agrees with the subject.

Yes. Depending on context, απλός / απλή / απλό can mean things like:

• simple
• plain
• uncomplicated
• basic

So Η μορφή είναι απλή could mean:

• the form is simple
• the shape is plain
• the structure is uncomplicated

The exact nuance depends on context.

Normally, no. In a standard sentence, you would usually say:

• Η μορφή είναι απλή.

Greek often uses the definite article where English might or might not use the, and here η is the normal choice for the form.

If you removed the article, the result would sound incomplete or unnatural in ordinary usage.

You add δεν before the verb:

• Η μορφή δεν είναι απλή.
  The form is not simple.

This is the normal way to negate είναι in modern Greek.

A common way is to keep the same words and use question intonation in speech:

• Η μορφή είναι απλή;

You can also change the word order:

• Είναι απλή η μορφή;

Both mean:

• Is the form simple?

In writing, modern Greek often uses the Greek question mark, which looks like a semicolon:

• Η μορφή είναι απλή;

Because it is the first word of the sentence, so it is capitalized.

• lowercase: η
• uppercase: Η

This is just like English capitalizing the first word in a sentence:

• The form is simple.

So:

• η μορφή είναι απλή becomes
• Η μορφή είναι απλή.