It's depend on where you live and certainly determines the license of a cryptocurrency trading market, not all countries give permission to trade cryptocurrencies
Use centralized exchanges that support fiat such as Binance, coinbase, Kucoin. All have apps and make sure you read the terms of use.
If you still find obstacles you can use a VPN and change your location to a country that provides convenience or legalizes cryptocurrency trading.
Please try go to further, and good luck with your brighter future