El conseguir una cita previa no siempre es fácil.

In Spanish, an infinitive like conseguir can function like a noun, similar to English getting.

So:

• conseguir una cita previa = getting an appointment
• el conseguir una cita previa = the getting of an appointment / getting an appointment

The article el makes the infinitive phrase feel more clearly like a noun phrase. It can sound a bit more formal, abstract, or emphatic.

You can also say:

• Conseguir una cita previa no siempre es fácil.

That is also correct and often feels a little more neutral.

Cita previa is a very common fixed expression in Spain. It means a pre-booked appointment or appointment made in advance, especially for:

• government offices
• medical services
• administrative procedures
• banks and similar services

So it is not just any date or meeting. In Spain, pedir cita previa is a very common phrase for arranging an official appointment ahead of time.

Spanish normally uses the infinitive where English often uses an -ing form.

Compare:

• English: Getting an appointment is not always easy.
• Spanish: Conseguir una cita previa no siempre es fácil.

Spanish does not usually use the gerund (consiguiendo) as the subject in this kind of sentence.

So:

• Conseguir una cita previa... = correct
• Consiguiendo una cita previa... = not natural here

Because the whole phrase el conseguir una cita previa is treated as one thing, one idea.

That entire infinitive phrase is the subject:

• El conseguir una cita previa = the act of getting an appointment

Since that subject is understood as singular, the verb is singular:

• ...es fácil

Not:

• ...son fáciles

In Spanish, no siempre means not always, and that is the normal way to express partial negation.

• No siempre es fácil = It is not always easy

Siempre no is not the normal wording for this meaning.

So the natural structure is:

• no siempre + verb/adjective

Examples:

• No siempre es posible.
• No siempre tengo tiempo.

Yes, absolutely. That is very natural, and many speakers would probably find it more straightforward in everyday use.

Compare:

• El conseguir una cita previa no siempre es fácil.
• No siempre es fácil conseguir una cita previa.

Both mean the same thing.

The second version often sounds:

• a bit more conversational
• less formal
• more direct

The first version puts extra focus on the act of getting an appointment.

Because the sentence is talking about getting an appointment in general, not one specific appointment.

• una cita previa = an appointment / any appointment
• la cita previa = the specific appointment

Here the idea is general:

• getting an appointment is not always easy

So the indefinite article una is the natural choice.

It can sound a little more formal, written, or abstract than simply using the infinitive without the article.

These all work, but with slightly different feel:

• El conseguir una cita previa no siempre es fácil.
  Slightly more formal or emphatic.

• Conseguir una cita previa no siempre es fácil.
  Neutral and very common.

• No siempre es fácil conseguir una cita previa.
  Very natural and fluid.

So yes, el + infinitive is correct, but it can sound a bit more elevated depending on context.

Because cita previa is a thing, not a person.

In Spanish, the personal a is used mainly with specific people (and sometimes personified animals).

Examples:

• Veo a María.
• Busco a mi profesor.

But:

• Busco una cita previa.
• Quiero conseguir una cita previa.

Since una cita previa is not a person, there is no personal a.

Because the subject is singular: el conseguir una cita previa.

The sentence is saying that this action is easy or not easy. That action is treated as one singular idea.

So:

• El conseguir una cita previa no siempre es fácil.

Not:

• ...fáciles

Also, fácil has the same form for masculine and feminine singular, so the important contrast here is really singular vs. plural.

Usually the meaning is very close, but el conseguir can feel a bit more like the act/process of getting something.

Compare:

• Conseguir una cita previa no siempre es fácil.
  Getting an appointment is not always easy.

• El conseguir una cita previa no siempre es fácil.
  The act of getting an appointment is not always easy.

In many real contexts, the difference is small. It is more about style and focus than major meaning.

Yes, other verbs could work, but conseguir is very natural here because it often means:

• to manage to get
• to obtain
• to secure

That fits well with appointments, especially when they may be hard to get.

Possible alternatives:

• obtener una cita previa — more formal
• lograr una cita previa — possible, but a bit less common here

In everyday Spanish in Spain, conseguir una cita previa sounds very natural.

It is especially common in Spain, particularly in public administration and services.

A learner of Spanish in Spain will see and hear it often in contexts like:

• Necesita cita previa
• Solicite cita previa
• Pedir cita previa online

In other Spanish-speaking countries, people may understand it, but other expressions may be more common depending on the region and institution.

Yes. This is very common in Spanish.

Examples:

• Fumar es malo. — Smoking is bad.
• Viajar solo puede ser peligroso. — Travelling alone can be dangerous.
• Aprender español lleva tiempo. — Learning Spanish takes time.

So in your sentence:

• (El) conseguir una cita previa is the subject

This is one of the most important differences from English, where learners often expect an -ing form instead.

Yes, but with a nuance.

El conseguir una cita previa no siempre es fácil is correct and natural enough, especially in:

• written Spanish
• news or formal commentary
• administrative or explanatory contexts

In casual speech, many speakers would more often say:

• No siempre es fácil conseguir una cita previa.
• Conseguir una cita previa no siempre es fácil.

So the original sentence is good Spanish, but not necessarily the most everyday-sounding version.