How do I add an extra spell to my spells know list? 

Example one of my players a wizard 2/ druid 3 found a scroll of animate dead. They wish to copy the scroll in to their spellbook. How do I do this with the D&D beyond character sheet?

In the Spells section, click Manage Spells, and then in the sidebar, under Wizard click on Add Spells, and then click the Learn button on the spell you want to add.

However, since they are only a 2nd-level Wizard, you can only add 1st-level spells to their spellbook. They'll need to hold onto the Animate Dead spell scroll until Wizard 5, at which point they'd be able to copy in 3rd-level spells.

Thanks for the reply.

I was hoping there was a way to add regardless of system requirements. Like in a homebrew or custom ruling. 

sorry i should have been more specific.

No, the system is designed to support RAW, and it is directly against RAW for a 2nd level Wiz to add a 3rd-level spell to their book. (They couldn’t cast it anyway.) If they just sit on the scroll they can add it in a couple levels.

Several years too late, but for any future searchers- you don't have limits on being able to add Feats, and there are Feats that allow you to cast certain spells. Might do what you need! :)

ive been gifted a spell by an ancient power Lvl 5 spell of Scrying- how do I add that to my list of spells (im a Rnager at lvl8)

Quote from RayMac >>

ive been gifted a spell by an ancient power Lvl 5 spell of Scrying- how do I add that to my list of spells (im a Rnager at lvl8)

 
You could create a homebrewed feat and add it to your character sheet. That’s how people generally deal with boons such as that.

Not much use when the spell you want to add is from a book you don't own, but that is shared with the campaign characters, because you can't create the homebrew feat containing that spell. Pretty ridiculous there STILL isn't a way to do this properly. 

Quote from Kara_shadow_stare >>

Not much use when the spell you want to add is from a book you don't own, but that is shared with the campaign characters, because you can't create the homebrew feat containing that spell. Pretty ridiculous there STILL isn't a way to do this properly. 

 
Well, either the person who owns the book can make the feat for you, or you could recreate the spell and add that version to the feat.

Hello! I created a homebrew subclass for my rogue and enabled spell casting, but it doesn't show up on the character sheet. Is there something I'm missing? The subclass I made is called Arcane Assassin, and I'm working on a different version with any fixes I need to make.