Some are still using bitcoin core but many people prefer to use non-custodial wallet which doesn't need to download whole blockchain which takes up a lot of space. There are wallets you can use like electrum, trustwallet and many more wallet that are non-custodial.
Just a heads up:
1. Bitcoin Core is also a non-custodial wallet
2. You don't necessarily need to download the entire blockchain if your computer doesn't have enough memory. Lookup pruned nodes, where you can only download like 15gb and such.