Which currency pair should a beginner choose?

To begin with, I recommend that you choose a reliable broker https://tradersunion.com/interesting-articles/best-forex-trading-platform-for-beginners/ , if you have already done this, then I answer your question, I advise you to start working with major currencies and such currency combinations, in a pair of which there is a dollar. For example, beginners trade well with "classic" EUR/USD or GBP/USD pairs, you can also successfully trade NZD/USD or AUD/USD pairs, good luck.