I see a lot of answers on here that are misleading or confusing. One problem with economics is it's really a bunch of made-up mind games related to social sciences, which in turn has led to all kinds of conspiracy theorists and cults even within more mainstream economics and some really crazy stuff at the fringes.

The topic of inflation seems to be particularly of interest to conspiracy theorists who all claim to know exactly why it happens, who is to blame and how to fix it (it often sounds like "Government blah blah blah gold standard"...). The truth is there are some strong, well-researched but ultimately incomplete explanations regarding inflation, but really nobody knows.

So here is my understanding of the best current guesses about the topic:

Ignoring the specific example of Venezuela for a second. At a basic theory level: Inflation in country A does not depend on external currencies nor does it matter how much country A imports or exports or if they trade at all.

Imagine a closed off country with no international currency exchange and no external trade. For some reason, it doesn't matter why really, citizens there expect prices for things to go up (maybe it's an island running out of space so landlords raise rents or maybe the government is increasing taxes or maybe everyone on the island is just really lazy wanting to sit on the island's beaches all day thus it is taking increasingly more $ to get anyone to get up and do anything one might need help with)...

The citizens expectation of future higher prices leads those in the economy who sell a product or service and who can charge more for it to do so immediately (as they prepare for future higher expenses they will soon face). Specifically, the producers of inelastic goods like farmers who grow food or oil companies will do better in this scenario than regular employees who suffer more as they can't get an increase in salary so easily. But really everyone starts to struggle.

Depending on how high prices are increasing, citizens may start soon switching to bartering and looking to store value in other ways other than their currency (like gold coins or magic the gathering card collecting, etc). Barter is not always possible and most landlords won't accept rent payment in the form of your magic card collection, not directly anyway. Where money is still used and accepted, people will try to get rid of any money they receive as soon as possible (as it's increasingly less valuable putting it in a savings account is bad). So people try to get their money into anything but a savings account and buy as quickly as possible something they need immediately or something that is a store of value. This is inflation and potentially hyperinflation without any international currency exchange or trade.

Now, where a country is able to engage in trade with other countries (for good and services or sell each other debt), this will influence the economy and inflation there. And depending too much on imports one can't be sure they can afford is very bad. But external currencies doesn't cause inflation, rather currency exchanges become a mirror to reflect a country's relative credit-worthiness and growth prospects, as well as any inconveniences connected to the fact people don't want or need another country's currency so where someone does accept foreign currency they must be compensated for the process, time and risk of getting payment in a form they do want.

The closed off simple economy thought experiment is quite useful and established, here is wiki link to the most basic version, one dude on island aka the Robinson Crusoe economy https://en.wikipedia.org/wiki/Robinson_Crusoe_economy