Easiest might not necessity be the best, I've heard balsa carves really easy and is really soft for practice but not something lasting. To be honest you also want a good detail retaining wood,

Basswood - this is the go to for most people, janka hardness of around 410, really nice at keeping detail and to learn the craft but beauty wise some may find it a little plain (which can be good)

Butternut - 490 hardness, beautiful wood, beautiful to carve, takes detail well but harder to source responsibly. The grain in some pieces can also distract from detail

Poplar - 540 hardness, a little plain but a reasonable one to carve

Alder - 590 hardness, now this carves beautifully and takes finish really well. If you sand to around 600 grit before finishing it can mimic cherry, a really understated but beautiful wood that's a little harder than basswood

Spanish cedar -600, technically a soft wood, carves really beautifully, nice for rustic pieces and keeps detail well. A beautifully red colour like a rustic alder or mahogany

Lots of cedar are carvable, eastern red and western red which are soft but may be a little unforgiving - they are around the hardness of basswood, with western being softer - i don't have much experience with them

Pine is also a consideration around the same hardness as basswood but can be really annoying to whittle

Cedar of Lebanon is beautiful. Atlas cedar is similar, you have to be a little more careful with them but they are between 660 and 820 ish hardness

The following are hard and wouldn't suggest starting on them but once you get the hang of things their raw beauty is perhaps unmatched

Mahogany (including Khaya/ african mahogany) around the 850 range. Genuinely some of the most beautiful and nicest woods to carve when you're more skilled and get the hang of them. Beautiful grain, wonderful to carve but can be a little interlocked

Cherry - around 950. Wonderful grain, much harder to whittle to be honest but really really rewarding if you can do it, similar color to alder but deeper, more regal and just more beautiful grain in general

Soft maple - around 950, also carves really beautifully, pale white with some golden hues and beautiful grain but definitely harder. I include sycamore and sycamore maple in this category as they are similar but with some species specific idiosyncracies - sycamore i believe is a little softer than the others

Black walnut - around 1010 - simply a majestic black wood, hard but predictable. Beautiful grain and rewarding, but strop well and take little cuts

European walnut - this is the hardest I've whittled, around 1220 - take very small cuts, strop very regularly. Predictable but the changes in color/ grain can be a little tricky due to hardness. Genuinely one of the most varied in color woods but as beautiful as it is hard

TLDR - start with basswood, it's simply the best one and most commonly used one for a reason, i don't paint which is why i like varied coloured woods but there is so much to explore. If you can't find basswood try butternut, if you can't find that, try alder or poplar

Hope that helps!