Pagamos el saldo pendiente.

Because Spanish often drops subject pronouns when they are clear from the verb ending.

Pagamos already tells you the subject is we. So Pagamos el saldo pendiente is perfectly natural.

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

Ellos no pagaron; nosotros pagamos.
They didn’t pay; we did.

It can mean either one.

Pagamos is ambiguous between:

• present tense: we pay
• preterite / simple past: we paid

The context tells you which meaning is intended.

Examples:

• Cada mes pagamos el saldo pendiente.
  Here it means we pay
• Ayer pagamos el saldo pendiente.
  Here it means we paid

This is a very common question because the nosotros form is identical in these two tenses for many verbs.

Because Spanish often uses the definite article when talking about a specific, known thing.

So el saldo pendiente means the particular outstanding balance being referred to.

Compare:

• Pagamos el saldo pendiente. = we paid/are paying the outstanding balance
• Pagamos un saldo pendiente. = we paid an outstanding balance / one outstanding balance

In this sentence, el sounds most natural if both speaker and listener know which balance is meant.

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

So:

• saldo pendiente = outstanding balance

This is the normal order. In English, many adjectives go before the noun, but Spanish often places them after it.

Also, saldo pendiente is a very natural fixed combination in billing and finance contexts.

Yes. Spanish adjectives normally agree with the noun they describe.

Here:

• saldo is singular
• so pendiente is also singular

If it were plural, you would say:

• los saldos pendientes

A useful detail: pendiente has the same form for masculine and feminine in the singular:

• el saldo pendiente
• la factura pendiente

But in the plural it becomes pendientes.

Yes, that is grammatically correct.

But in normal Spanish, especially in everyday speech, the pronoun is usually left out unless there is a reason to include it.

So:

• Pagamos el saldo pendiente. = neutral, natural
• Nosotros pagamos el saldo pendiente. = more emphatic, contrastive, or explicit

For example:

Ellos no lo hicieron, pero nosotros pagamos el saldo pendiente.

Yes.

In Spain, the present perfect (hemos pagado) is very commonly used for actions completed in a time period that is still connected to the present, such as:

• hoy
• esta semana
• este mes

So in Spain, someone might naturally say:

Hoy hemos pagado el saldo pendiente.

By contrast, pagamos can be:

• simple present: we pay
• simple past: we paid

So the choice depends on the context. In Spain, hemos pagado is often preferred for a recent completed action with present relevance.

Because the personal a is mainly used with human direct objects, and saldo is not a person.

So you say:

• Pagamos el saldo pendiente.

But with a person, you might say:

• Vimos a Marta.

This is why there is no a in your sentence.

Yes, very much so.

In financial or billing language, saldo pendiente is a standard, natural phrase for an amount still unpaid.

A learner might think of English balance, but Spanish balance usually does not mean the same thing in this context. It often refers to things like:

• a financial statement
• a summary of accounts
• balance in the sense of equilibrium

So saldo pendiente is the better choice here.

The most neutral word order is:

Pagamos el saldo pendiente.

That is the standard verb + direct object pattern.

You can change the order, but then it usually adds emphasis or changes the focus. For example:

El saldo pendiente lo pagamos ayer.

That sounds more like: The outstanding balance, we paid it yesterday.

So the original order is the best default one.

In Spain, it is pronounced roughly:

pah-GAH-mos

A few helpful points:

• g in pagamos is a hard g, like in go
• the stress falls on ga
• the final s is clearly pronounced in standard Spain Spanish

So the full sentence sounds roughly like:

pah-GAH-mos el SAL-do pen-DYEN-te

That is only an approximation, but it is a useful guide for an English speaker.