Debemos marchar ahora.

Debemos is the present tense, first person plural form of deber.

• deber = to owe / to have to / must
• debemos = we must / we have to

In this sentence, it expresses obligation: we must.

In standard Spanish, deber + infinitive usually expresses obligation:

• Debemos marchar = We must leave

Deber de + infinitive traditionally expresses probability or assumption:

• Deben de ser las ocho = It must be around eight

In everyday speech, some speakers mix these patterns, but for learners it is best to remember:

• deber + infinitive → obligation
• deber de + infinitive → probability

So Debemos marchar is the expected form here.

Here, marchar means something like to leave, to go, or to depart.

Depending on context, marchar can also mean:

• to march
• to go away
• to function/go well in expressions like La cosa marcha bien

In Debemos marchar ahora, it most naturally means to leave or to go now.

Yes, marchar is perfectly natural in Spain, especially in the sense of leaving.

Other common alternatives are:

• Debemos irnos ahora = We must leave now
• Tenemos que irnos ahora
• Hay que marcharse ya = One has to leave now / We need to leave now

In Spain, marchar(se) can sound very natural in spoken language. In some other Spanish-speaking regions, irse may be more common.

Spanish often omits subject pronouns because the verb ending already shows who the subject is.

• debemos clearly means we
• So Nosotros debemos marchar ahora is possible, but usually unnecessary

You would add nosotros only for emphasis, contrast, or clarity:

• Nosotros debemos marchar ahora, pero ellos pueden quedarse.

So the version without the pronoun is the most normal one.

Yes, ahora can move around, but the most natural position here is at the end:

• Debemos marchar ahora.

Other possible placements:

• Ahora debemos marchar.
• Debemos ahora marchar. (less natural in everyday speech)

Placing ahora first can give it a bit more emphasis:

• Ahora debemos marchar = Now we must leave

But the original word order is very standard and natural.

Yes. Debemos marchar ahora and Tenemos que marchar ahora are both correct and very similar.

• debemos + infinitive = we must
• tenemos que + infinitive = we have to

In many situations, they are interchangeable. Sometimes debemos can sound slightly more formal or slightly stronger, but the difference is often small.

The verb debemos is in the present indicative.

Even though it is present tense in form, it often refers to a present obligation about the immediate future:

• Debemos marchar ahora = We must leave now

So grammatically it is present tense, but the action of leaving is something that needs to happen right away.

A rough pronunciation for an English speaker is:

deh-BEH-mos mar-CHAR ah-OH-ra

A few notes:

• b in debemos is softer than English b
• ch in marchar sounds like English ch in church
• r in marchar is a tapped Spanish r
• h in ahora is silent

In most of Spain, c before e/i and z have a th sound, but that does not affect this sentence.

You can hear both marchar and marcharse, depending on context and nuance.

• marchar = to leave / to go
• marcharse = to go away / to leave, often with a clearer sense of departing

In many cases, they are very close:

• Debemos marchar ahora
• Debemos marcharnos ahora

Both are possible. The reflexive form marcharse is also very common when talking about people leaving a place. The non-reflexive version in your sentence is still correct and natural.

It sounds neutral to slightly formal, depending on context.

• Debemos marchar ahora can sound a bit more polished or deliberate
• Tenemos que irnos ahora may sound a little more conversational in everyday speech

That said, Debemos marchar ahora is not overly formal. It is completely normal Spanish.

Yes. Marchar can mean to march in the military or literal walking-in-step sense.

For example:

• Los soldados marchan = The soldiers march

So the verb has more than one meaning. In your sentence, though, because of the context and ahora, learners should understand it as to leave or to go.

Yes. Depending on context, possible translations include:

• We must leave now
• We have to leave now
• We must go now
• We need to go now

The exact English choice depends on the situation, but the Spanish structure stays the same.