Upvote:1
My answer will focus specifically on Schengen.
Generally they just ask you to show enough funds for the trip that's motivating your request for a visa, per requirements of the country that will grant your visa. For the Netherlands, for example, you need 55€ per person per day.
The proof of funds can be done through several means, including:
Some other things that they also accept as partial proof of funds but will not be sufficient for complete proof (but might be able to let you go through carrying less cash or cash-equivalents)
The more you can prove that you have a planned trip and made your arrangements beforehand, the better.
If you're from a country that has unstable exchange rate for the local currency, they're very understanding with pre-loaded travel cards carrying high amounts of currency, as this is a form of protecting yourself from exchange rate fluctuation before the trip.