Prima di fare il check-out, lascio la chiave magnetica alla receptionist.

In Italian, prima di + infinitive is the normal pattern for before doing something.

• prima di fare il check-out = before checking out
• prima di partire = before leaving

So di is required here because it links prima to the infinitive fare.

Because in Italian, many borrowed English nouns are turned into actions with fare.

So:

• fare il check-out = to check out
• fare shopping = to go shopping
• fare jogging = to go jogging

Italian generally does not use check-out directly as a verb the way English does.

Italian usually needs an article before nouns, even with many English loanwords.

So:

• fare il check-out
• fare il login
• fare il test

English often says check out without an article because it is a verb phrase, but in Italian check-out is treated as a noun, so it normally takes il.

Italian often uses the simple present to talk about:

• habits
• routines
• scheduled actions
• general statements

So lascio la chiave magnetica alla receptionist can mean something like:

• I leave the key card with the receptionist
• I hand the key card to the receptionist

It sounds natural if you are describing what you do as part of a usual process.

If you wanted to talk about a future action more explicitly, you could also hear:

• lascerò la chiave magnetica... = I will leave the key card...

But the present tense is very common here.

Chiave magnetica is a common Italian way to refer to a hotel key card or magnetic key.

Literally:

• chiave = key
• magnetica = magnetic

So even if English speakers often say key card, Italian may say chiave magnetica.

You could also hear:

• tessera magnetica
• carta magnetica in some contexts

But chiave magnetica is very natural for a hotel.

Alla = a + la.

The preposition a is used for the person who receives something, similar to an indirect object:

• Do il libro a Marco = I give the book to Marco
• Lascio la chiave alla receptionist = I leave the key with / to the receptionist

Because receptionist here is feminine, Italian uses la, and a + la becomes alla.

The noun receptionist in Italian is generally invariable, meaning its form does not change between masculine and feminine. The article tells you the gender.

• il receptionist = the male receptionist
• la receptionist = the female receptionist

In your sentence, alla receptionist shows that the receptionist is female.

If the receptionist were male, it would be:

• lascio la chiave magnetica al receptionist

Yes, depending on what you mean.

• alla receptionist = to the receptionist (the person)
• alla reception = at/to the reception desk or front desk (the place)

So:

• Lascio la chiave magnetica alla receptionist emphasizes the person receiving it.
• Lascio la chiave magnetica alla reception emphasizes where you leave it.

Both can be natural.

The opening phrase Prima di fare il check-out is an introductory time expression, and a comma is commonly used after it for clarity.

So the sentence is structured like this:

• Prima di fare il check-out, = before checking out,
• lascio la chiave magnetica alla receptionist. = I leave the key card with the receptionist.

The comma helps separate the introductory part from the main clause. In short sentences, punctuation can vary a little, but the comma is very normal here.

Yes. The choice changes the nuance slightly.

• lascio = I leave
• do = I give
• consegno = I hand in / hand over

Examples:

• Prima di fare il check-out, do la chiave magnetica alla receptionist.
• Prima di fare il check-out, consegno la chiave magnetica alla receptionist.

Lascio sounds very natural if you mean you leave it there with her.
Consegno sounds a bit more formal or precise.

Yes. A very natural version would be:

• Prima di fare il check-out, gliela lascio.

Here:

• glie- = to her / to him
• la = it (the key)
• lascio = I leave

So gliela lascio means I leave it with her or I give it to her.

If the noun has already been mentioned, this pronoun version is very common.

Fare il check-out is common and widely understood, especially in hotel contexts. But Italian also has alternatives, such as:

• prima di lasciare la camera = before leaving the room
• prima di partire = before leaving / departing
• al momento del check-out = at check-out time

So check-out is natural, but it is not the only possible wording.

Yes. Italian word order is flexible, although the original sentence is very natural.

Original:

• Prima di fare il check-out, lascio la chiave magnetica alla receptionist.

Possible variations:

• Lascio la chiave magnetica alla receptionist prima di fare il check-out.
• Alla receptionist lascio la chiave magnetica prima di fare il check-out.
  This puts more emphasis on alla receptionist.

The original version is probably the most neutral and straightforward.