Quiero envolver el regalo con papel azul y un lazo bonito.

Because after querer (to want), Spanish normally uses an infinitive for the next verb.

• quiero = I want
• envolver = to wrap

So quiero envolver literally means I want to wrap.

You would not say quiero envuelvo, because envuelvo is already a conjugated form (I wrap), and Spanish does not usually put two fully conjugated verbs together like that.

Yes, it is irregular in some forms. It is a stem-changing verb: o → ue in many present-tense forms.

For example:

• yo envuelvo
• tú envuelves
• él/ella envuelve

But in your sentence it appears as envolver, the infinitive, because it comes after quiero.

So:

• Envuelvo el regalo = I wrap the gift
• Quiero envolver el regalo = I want to wrap the gift

El regalo means the gift, so it refers to a specific gift, probably one already known in the situation.

Spanish uses the definite article very naturally when the speaker has a particular thing in mind.

• el regalo = the gift
• un regalo = a gift

So this sentence suggests the speaker is talking about one particular present, not just any present.

In Spanish, material nouns like papel, agua, vino, etc. are often used without an article when speaking in a general way.

So:

• con papel azul = with blue paper

This sounds natural if you mean the wrapping material in general.

If you say con un papel azul, it can sound more like with a blue sheet/type of paper, emphasizing one particular piece or kind of paper.

Both are possible, but con papel azul is very natural here.

Because in Spanish, adjectives usually come after the noun.

So:

• papel azul = blue paper
• lazo bonito = pretty bow

This is the normal order in Spanish. English usually puts adjectives before the noun, but Spanish usually puts them after.

Because azul is one of those adjectives that does not change for masculine and feminine in the singular.

So you get:

• papel azul (masculine singular)
• caja azul (feminine singular)

But in the plural it does change:

• papeles azules
• cajas azules

So azul stays the same in singular, but becomes azules in plural.

Because lazo is a masculine singular noun.

That means:

• article: un
• adjective: bonito

They have to agree with the noun:

• un lazo bonito
• dos lazos bonitos

If the noun were feminine, the forms would change:

• una cinta bonita

So the masculine forms here come from lazo being masculine.

Not exactly.

• lazo = bow, especially the decorative bow tied on a present
• cinta = ribbon, the strip of material itself

So in gift-wrapping:

• papel = wrapping paper
• cinta = ribbon
• lazo = bow

In this sentence, un lazo bonito means a nice decorative bow on the gift.

Because, again, adjectives usually come after the noun in Spanish.

• un lazo bonito = a pretty bow

This is the most neutral and common order.

Sometimes Spanish can place adjectives before the noun, but that often changes the tone or emphasis. For a straightforward description, lazo bonito is the normal choice.

Yes, you could, but it sounds a little different.

• un lazo bonito = a bow that is pretty; neutral description
• un bonito lazo = a lovely/nice bow; slightly more expressive or literary

Both are grammatical. For everyday straightforward speech, un lazo bonito is the safer and more neutral option.

Yes. In this sentence, con naturally covers both things:

• con papel azul y un lazo bonito
• with blue paper and a pretty bow

So the idea is that the gift will be wrapped using blue paper and also a pretty bow.

Spanish often does this without repeating the preposition when the structure is clear.

Yes. In natural English, wrap the gift in blue paper is often the most natural translation, even though Spanish uses con here.

So:

• envolver el regalo con papel azul = to wrap the gift in blue paper

Spanish and English do not always use the same preposition in these situations.

Yes. Both are possible, but they sound different.

• quiero envolver... = I want to wrap...
  Direct and normal.
• quisiera envolver... = I would like to wrap...
  More polite, softer, or less direct.

So quiero is perfectly correct if you are simply stating what you want to do.

Partly.

• quiero is present tense: I want
• envolver is the infinitive: to wrap

So the whole sentence means something like Right now, I want to wrap the gift...

It expresses a present desire about an action.

Yes, and that is exactly what the sentence does.

Spanish often leaves out subject pronouns when the verb already makes the subject clear.

• (Yo) quiero envolver el regalo...

Because quiero clearly shows I, there is no need to say yo unless you want emphasis or contrast.

For example:

• Yo quiero envolver el regalo, no tú.
  I want to wrap the gift, not you.

You would change quiero to the correct form of querer.

For example:

• Quieres envolver el regalo con papel azul y un lazo bonito.
  You want to wrap the gift with blue paper and a pretty bow.

More forms:

• Quiero = I want
• Quieres = you want
• Quiere = he/she/you (formal) wants

The rest of the sentence can stay the same.

Most commonly, regalo means gift or present.

It is the standard word for something you give to someone.

Related words:

• regalo = gift/present
• regalar = to give as a gift

So el regalo here clearly means the present being wrapped.