I’m new to D&D and just started making my first character, she’s a wood elf druid. On the skill sheet there’s a section on “spellcasting ability”. I’ve tried looking elsewhere to find out how to calculate what it’d be but can’t find any way to do so. How do I find out what my spellcasting ability is?
Each spellcasting class will have a section in the class description where it describes what ability score is used for spell attacks and for spell save DCs. For a Druid, it’s Wisdom (page 66 of the Player’s Handbook):
Spellcasting Ability
Wisdom is your spellcasting ability for your druid spells, since your magic draws upon your devotion and attunement to nature. You use your Wisdom whenever a spell refers to your spellcasting ability. In addition, you use your Wisdom modifier when setting the saving throw DC for a druid spell you cast and when making an attack roll with one.
Note that it says “for your druid spells” in this quote. If you have the ability to cast spells from more than one source (such as multiclassing, a racial feature or a feat), you may have more than one spell casting ability. Each rule that gives you spell casting will tell you what ability to use for the spells it gives you.