Elemental Weapon (raw)

A nonmagical weapon you touch becomes a magic weapon. Choose one of the following damage types: acid, cold, fire, lightning, or thunder. For the duration, the weapon has a +1 bonus to attack rolls and deals an extra 1d4 damage of the chosen type when it hits.

At Higher Levels. When you cast this spell using a spell slot of 5th or 6th level, the bonus to attack rolls increases to +2 and the extra damage in creases to 2d4. When you use a spell slot of 7th level or higher, the bonus in creases to +3 and the extra damage in creases to 3d4.

This is the spell "Elemental Weapon" from the Player's Handbook, but with a different name so that the logic of linking things on dndbeyond doesn't conflict with the version locked behind the paywall.

Note that the system doesn't support the application of the to hit bonus, you'll have to keep track of that yourself.