Whatever you do, DON’T get a card smaller than the pre-packaged image. It is possible to reduce the image from 16 GB to 8 GB (I’ve done it to use an “old” SD card for testing purposes), but it’s infinitely harder than expanding an 8 GB image to 16 GB.
Balena Etcher is the recommended way to flash the card, and if you do get a 32 GB one, expanding the 16 GB image with GParted whilst still in your laptop/card writer to use all of it is very easy and quick.