There is a question that handles how the Order of Scribes wizard's Awakened Spellbook feature works with spells that have multiple damage types at the same time. However, those spells are rare.
There also are spells that allow you to choose one of a series of damage types (for example, Chromatic Orb, Elemental Weapon, Elemental Bane, Protection from Energy). Awakened spellbook says:
When you cast a wizard spell with a spell slot, you can temporarily replace its damage type with a type that appears in another spell in your spellbook, which magically alters the spell’s formula for this casting only.
How does Awakened Spellbook work with them? Can you use it at all? Can you change a damage type you can choose from? Or can you change the damage type once you have chosen it?
Best Answer
If your GM rules that spells with multiple damage types are eligible to have one of them replaced, you can replace any one of the choices, and choose the replacement.
Regardless of when you make the choice of which damage type you want for the spell, before you've made your choice you might be able to replace one of them (and then choose the replaced type).
If your GM rules that spells with multiple damage types are not eligible to have one of them replaced, it comes down to the GM's ruling on when the choice is made.
A spell with multiple damage types in a list that you choose from is a spell with multiple damage types before you cast it, but one damage type after you've chosen. Once you've made your choice and the spell has "a damage type," (rather than "damage types"; "a" is singular) it is definitely eligible to be replaced by Awakened Spellbook to replace that damage type.
However, does the choice happen too late? Importantly, the Awakened Spellbook feature can be used "when you cast" the spell—so if the choice is made after you cast the spell (and you're reliant on it only having one damage type to be eligible), it is too late to replace its damage type. So, is the choice made before or after you cast the spell?
The exact timing of that choice has not been clarified in the rulebooks or in Sage Advice, so your GM would need to make a ruling. The exact timing of other choices made regarding spellcasting could be useful in making this ruling: