The first and most important thing to take on a trip is documents and money. Keep them close to your heart, as they are the most important items to have while traveling. It's better to have a small bag or backpack that you will always carry with you and take as carry-on luggage during flights.
So, what to take with you:
Passport and its copies. In general, have copies of all your documents on your phone, USB drive, cloud storage/virtual disk, or email, and better be safe and choose several options. These copies may be needed if the originals are lost.
Printouts and electronic versions of hotel/apartment reservations, invitations from educational institutions, and confirmation of accommodation (if you are going to study).
Printouts and electronic versions of airline tickets.
Printouts and electronic versions of medical insurance. Don't forget the vaccination certificate if it's required to enter the country (for example, in several African countries, you won't be allowed without a valid certificate for yellow fever vaccination).
Minor students traveling without their parents' accompaniment need to have a notarized consent for independent travel signed by both parents. For the UK, a Consent Letter is also required.
Bank cards (it's better to have several cards and accounts from different banks). Life hack: keep money in accounts, not on cards, and transfer money directly before withdrawal using internet banking (preferably with VPN, we'll talk about it shortly). In this case, if your card is stolen, it will be empty since all the money will be stored in the account.
Some cash. Cash should always be at hand, in the currency of the country you are in. For example, during our trip to Morocco, we forgot twice to exchange our euros for local dirhams in advance, which caused us to have to exchange currency in difficult situations. Once in the late evening in Casablanca with the help of street money changers and police intermediaries, and the second time in the evening in the Sahara near the Algerian border with the villagers where we had to spend the night.
A small dictionary and phrasebook wouldn't hurt.
Download offline map apps like OSMAnd or Maps.Me on your mobile phone or tablet.
Don't forget to bring a power bank and a universal power adapter for sockets.
International driver's license and driving documents (power of attorney), as well as car documents, "green card," technical passport, inspection card, etc., when traveling in your car.
