Hay indicios en todas partes.

Because hay means there is / there are and is used to say that something exists or is present.

• Hay indicios = There are clues/signs
• Están indicios is not correct Spanish.

Use estar when you are talking about the location or state of something specific:

• Los indicios están en la mesa. = The clues are on the table.

But when you are introducing their existence in a place, Spanish normally uses haber:

• Hay indicios en todas partes.

It can mean either one. Hay is the same form for both singular and plural.

• Hay un indicio. = There is one clue/sign
• Hay indicios. = There are clues/signs

So in this sentence, because indicios is plural, hay means there are.

Indicios is the plural of indicio. It usually means signs, indications, clues, hints, evidence, depending on context.

It often suggests something indirect—something that points to a conclusion without stating it openly.

For example:

• Hay indicios de fraude. = There are signs/evidence of fraud.
• Hay indicios en todas partes. = There are clues/signs everywhere.

It is a bit more formal or abstract than pistas, which often feels more like literal clues in a mystery or investigation.

In Spanish, after hay, it is very common to use a noun with no article when talking about the existence of things in a general way.

• Hay libros en la mesa. = There are books on the table.
• Hay problemas. = There are problems.
• Hay indicios en todas partes. = There are clues/signs everywhere.

If you add an article, the meaning changes:

• Hay unos indicios... can sound like there are some particular clues...
• Hay los indicios... is generally not natural in this kind of sentence.

So no article is the normal choice here.

Because partes is a feminine plural noun.

• singular: parte
• plural: partes

The adjective or determiner must agree with the noun:

• toda parte would not be the normal expression here
• todas partes matches feminine plural

That is why the phrase is en todas partes.

Yes, en todas partes means everywhere or in all places.

It is a very common Spanish expression. Literally, it is something like in all parts/places, but in natural English it is usually just everywhere.

Examples:

• Te veo en todas partes. = I see you everywhere.
• Hay ruido en todas partes. = There is noise everywhere.

Yes. En todas partes and por todas partes are both common and often very close in meaning.

A rough tendency:

• en todas partes = everywhere
• por todas partes = all over the place / everywhere around

In many situations, either works:

• Hay indicios en todas partes.
• Hay indicios por todas partes.

Por todas partes can sometimes feel a little more vivid or scattered, as if the signs are spread all over.

Both are correct.

• Hay indicios en todas partes.
• En todas partes hay indicios.

The difference is mainly emphasis.

• Hay indicios en todas partes starts by introducing the existence of the clues.
• En todas partes hay indicios emphasizes everywhere first.

Spanish word order is often more flexible than English when the grammar is clear.

In most Latin American Spanish, hay is pronounced roughly like the English word eye, but with a slightly cleaner, shorter vowel.

So:

• hay ≈ eye

This is because the h is silent in Spanish.

Yes. Hay is a form of haber used to express existence.

You do not need to think of it as a normal person-based conjugation like tengo, tienes, tiene. In this use, hay works as a special impersonal form meaning there is / there are.

Related forms:

• hay = there is / there are
• había = there was / there were
• hubo = there was / there were
• habrá = there will be

Examples:

• Hay un problema.
• Había muchas personas.
• Habrá cambios.

Both. That is one reason the word is useful.

It can refer to:

• physical clues in an investigation
• signs that suggest something is true
• evidence pointing toward a conclusion

For example:

• La policía encontró indicios en la escena. = physical clues
• Hay indicios de que va a llover. = signs that it may rain
• Existen indicios de corrupción. = evidence/signs of corruption

So in Hay indicios en todas partes, the exact nuance depends on context.

Sometimes, but not always.

• pistas usually means clues, often in a mystery, investigation, or puzzle.
• señales often means signs, signals, or indicators.
• indicios often means indications, clues, evidence, signs and can sound a bit more formal or analytical.

So:

• Hay pistas en todas partes sounds more like detective-story clues.
• Hay señales en todas partes sounds more like visible signs or signals.
• Hay indicios en todas partes feels broader and a little more formal.

Yes, it is natural and correct.

It sounds fairly neutral and standard across much of the Spanish-speaking world, including Latin America. The exact feeling depends on context:

• in a detective or suspense context, it sounds like There are clues everywhere
• in a more abstract context, it sounds like There are signs everywhere

So it is a useful sentence pattern to learn:

• Hay + plural noun + en todas partes