You can use anything to animate, there are madmen who make frames by paper still, edit it with any art program, and then just put it together with a non linear editing program.
Personally, I use flash for the keys, then edit the frames with clip studio paint, which has a built in animation part that's pretty robust, but its pricey. If you have the bundle I think you can just do the same thing with photoshop. If you have premiere pro you should be able to edit it on that, though you'll have to learn some rudimentary editing. Opentoonz is nice cause its basically made specifically to emulate oldschool 2d editing. Kind of a weird interface, though.
If you're trying to get a job I'd recommend getting toonboom and figuring it out. It has some nice ease of use stuff and its the industry standard right now, for better or worse. plus its built around clean vector linework that's easily cleaned up. not good for varying line weight, but still good to know.
Take all of this with a grain of salt, as I'm a mere self trained poorfag that can't even dream of going to school and is just working on short films and demo reels to try and snag a job.