El proyecto involucra a todos.

Involucra is the 3rd person singular present indicative form of involucrar.

It is singular because the subject is El proyecto (the project), which is singular:

• El proyecto involucra... = The project involves...

It is not involucran because involucran would need a plural subject, such as:

• Los proyectos involucran a todos. = The projects involve everyone.

This is the personal a.

In Spanish, when the direct object is a person or refers to people, Spanish usually adds a before it. Here, todos refers to people (everyone / everybody), so Spanish uses:

• involucra a todos

Even though English does not use a preposition here, Spanish does.

Compare:

• El proyecto involucra a todos. = people → personal a
• El proyecto incluye todo. = things / everything → no personal a

So the a does not mean to here. It is just required because the object is human.

Here, todos means everyone or all of them, depending on context.

Because there is no noun after it, todos is standing on its own as a pronoun:

• a todos = everyone / everybody / all of them

If a noun were included, it would mean all + noun:

• a todos los estudiantes = all the students
• a todos los empleados = all the employees

So in this sentence, todos is a short way of referring to all the people concerned.

Todos is the masculine plural form, but in Spanish it is also the default form for a mixed group or when the gender is unspecified.

So:

• todos = all of them / everyone (mixed group or unspecified)
• todas = all of them (all female)

If the sentence were specifically about a group of women, you could say:

• El proyecto involucra a todas.

But if the group is mixed or unknown, todos is the normal form.

Here it is a pronoun.

That is because it appears without a noun after it:

• a todos → pronoun

If it came before a noun, it would function more like a determiner/adjective:

• a todos los trabajadores
• a todos los vecinos

So in El proyecto involucra a todos, todos means all of them / everyone by itself.

El is the definite article, meaning the.

So:

• El proyecto = the project

Spanish often uses articles in places where English does too, and sometimes even where English might omit them. In this sentence, El proyecto refers to a specific project already known from the context.

If you wanted to say a project instead, you would say:

• Un proyecto involucra a todos.

That changes the meaning from a specific project to any/one project.

Possibly, depending on context, but involucra most directly means involves.

The verb involucrar suggests that people are included in, connected to, or drawn into something.

Possible English translations depending on context:

• The project involves everyone. ← most direct
• The project includes everyone. ← possible in some contexts
• The project affects everyone. ← possible if the idea is impact, but less exact

If the intended idea is mainly affecting people, Spanish might also use afectar:

• El proyecto afecta a todos.

If the idea is that people are engaged or implicated, involucrar works very well.

Yes, often you can, but there is a nuance.

• El proyecto involucra a todos.
• El proyecto implica a todos.

Both can mean something like The project involves everyone, but:

• involucrar often suggests active participation or being drawn into something
• implicar can sound a bit broader, like to involve, to entail, or even to implicate, depending on context

In Spain, implicar is also very common. In many everyday situations, either verb may work, but they are not always perfectly interchangeable.

Yes, but El proyecto involucra a todos is the most neutral and standard order.

Spanish word order is flexible, so for emphasis you might move parts around, but that usually makes the sentence more marked.

Neutral:

• El proyecto involucra a todos.

More emphatic or marked:

• A todos involucra el proyecto.

That second version is grammatical, but it sounds less neutral and would usually be used for emphasis or style. For most learners, the original order is the safest and most natural choice.

Because Spanish normally does not need subject pronouns unless they are needed for emphasis, contrast, or clarity.

The subject is already expressed by the noun:

• El proyecto involucra a todos.

Adding él would usually be unnecessary:

• Él, el proyecto, involucra a todos. ← unnatural here

Spanish is a language that often leaves out subject pronouns because the verb form and context usually make the subject clear.

A very natural Spanish version would be:

• El proyecto nos involucra a todos.

Here:

• nos = us
• a todos = all of us / all of everyone, depending on context

This structure is very common in Spanish: the object pronoun appears before the verb, and a todos adds emphasis or clarification.

So:

• El proyecto involucra a todos. = The project involves everyone.
• El proyecto nos involucra a todos. = The project involves all of us.