Buying through apps
The easiest way to obtain cryptocurrency is by buying through an online crypto wallet service or app.
All of the listed providers I use regularly, have significant accounts with, and have treated me well.
Coinbase is one of the earliest and largest brokers in North America with an easy to install app for Android and Apple devices.
Crypto.com is one of largest brokers in the Asia-Pacific region with headquarters in Hong Kong and Singapore.
Celsius Network straddles the UK and US. While primarily in the crypto lending space (more on that later), they offer integrated crypto purchases.