If you are asking about the simplest form of DOGE purchase, in my opinion it will be easiest for you to buy on Binance.
Binance is currently the largest crypto exchange in the world and enjoys a lot of trust.
It is also very convenient that if you make withdrawals up to 0.06BTC per day, you do not have to undergo KYC verification, and this, apart from making things a lot easier, makes opening your account and making transactions much faster.