Bárki beléphet.

Bárki means anyone / anybody.

It is made up of:

• ki = who
• bár- = a prefix that gives the sense of any-, no matter who

So bárki is an indefinite pronoun meaning any person at all.

Beléphet means can enter or may enter.

It comes from:

• belépni = to enter, literally to step in
• be- = in, into
• lép = step
• -het = a suffix meaning can / may / is allowed to

So beléphet is the third person singular form:
he/she/it can enter, or with bárki as the subject, anyone can/may enter.

It can mean both.

The suffix -hat/-het can express:

• ability / possibility = can
• permission = may

So depending on context, Bárki beléphet could mean:

• Anyone can enter.
• Anyone may enter.
• Entry is open to everyone / unrestricted.

On a sign or in a rule, English would often translate it as Anyone may enter or Anyone can enter.

Because Hungarian often expresses that meaning with a verb suffix instead of a separate helping verb.

In English:

• can enter
• may enter

In Hungarian, that idea is built into the verb:

• beléphet

So the sentence is short because Hungarian packs more information into the verb itself.

Be- is a verbal prefix. It adds the meaning in / into.

So:

• lép = step
• belép = step in / enter

In Hungarian, these prefixes are often written together with the verb when nothing separates them.

So in this neutral sentence:

• Bárki beléphet.

the prefix stays attached.

But in other sentence patterns, it can move:

• Bárki léphet be.

This is also grammatical, but the word order gives a slightly different emphasis.

This is the most neutral, straightforward word order:

• Bárki = subject
• beléphet = verb

So it simply states the fact or rule:
Anyone can/may enter.

Hungarian word order is flexible, but changes in order often change emphasis, not basic meaning.

For example:

• Bárki beléphet. = neutral
• Beléphet bárki. = stronger focus on the fact that entry is allowed
• Bárki léphet be. = also possible, with different information focus

For a learner, the given sentence is the safest neutral version.

This is a very common question.

• bárki = anyone / anybody
• mindenki = everyone / everybody

They are similar, but not identical.

Bárki beléphet means:

• there is no restriction on who
• any person is allowed / able to enter

Mindenki beléphet means:

• everyone can enter
• it sounds more like talking about the whole group collectively

In many contexts they may feel close, but bárki stresses any individual person whatsoever.

Yes. It is a perfectly complete Hungarian sentence.

Hungarian does not need extra words like one, people, or they here.
The subject is already present as bárki, and the verb beléphet is fully inflected.

So the sentence is natural and complete exactly as it is.

Yes, but it means something different.

• Bárki beléphet = Anyone can/may enter
• Bárki belép = Anyone enters / anyone is entering

Without -hat/-het, the sentence loses the meaning of can / may.

So if you want to express permission or possibility, you need beléphet, not just belép.

It is neutral standard Hungarian.

It works in many situations, for example:

• rules
• signs
• announcements
• everyday speech

It does not sound especially formal or especially casual.
It is a normal, natural way to say that entry is open to anyone.

A simple pronunciation guide:

• Bárki ≈ baar-kee
• beléphet ≈ beh-LAYP-het

A few helpful points:

• á is a long a sound
• é is a long ay-like sound
• stress in Hungarian is always on the first syllable of each word:
  • BÁRki
  • BEléphet

So the rhythm is roughly:

BÁR-ki BE-lép-het

Yes, absolutely.

Bárki beléphet can work very well in that kind of context. It naturally conveys that there is no restriction on who may enter.

Depending on style, a sign might also use other wording, but this sentence is clear and idiomatic.