Out of all free programs, I find Krita the best option for making art! It's completely safe to use. FireAlpaca is also a pretty good free art software!
However if you are getting into digital art and want an upgrade in the future, I would recommend investing in Clip studio Paint! The price is really budget-friendly and it's a great program that's optimized for comic making. Also, If you own an Ipad I really recommend Procreate, it's one-time payment (I don't recall the exact price but I think it's around 10$?). Clip studio Paint's Ipad version is also extremely good, I've been using it for more than a month now and I'm really happy with it!