I included this in my DELVE setting rules, but I'm posting it separately for better visibility. These are rules I came up with for creating magic scrolls in a fantasy setting. For the purposes of these rules, I use Artifice (Mechanics) as the key skill, but you could just as easily use Knowledge: Lore.

Artifice is also used in the creation of scrolls. Scrolls are magic spells bound into carefully inscribed parchment, and can only be cast once, at which point the scroll itself is consumed. Anyone can cast a spell from a scroll, but only someone with ranks in Arcana, Divine, Primal, or Verse may create a scroll. Mentalism is specifically excluded from eligible magic skills for the purposes of crafting scrolls.

In order to create a scroll, you must first determine the spell you wish to inscribe, including any specific effects you wish to include. No difficulty reductions, from implements or by any other means, are allowed when creating a scroll. The final difficulty of the spell is the difficulty of the Artifice skill check to create the scroll.

Next, you must have the materials to create the scroll: fine vellum, expensive inks, binding agents, etc. The cost of materials needed to create a scroll depends on the difficulty of the spell being inscribed:

The materials required to create a scroll are consumed whether or not the scroll is successfully inscribed (although a surplus of Advantage on a failed check may allow you to salvage some portion of the materials, at the GM's discretion).

Once you have selected the spell to be inscribed, and have acquired the materials with which to create the scroll, you may attempt to create the scroll. The base time required to create a scroll is one hour per level of difficulty. Make an Artifice (Intellect) skill check against the difficulty level of the spell. If you succeed, the spell is successfully inscribed, and the scroll created. Advantage may be spent to reduce the time required to complete the scroll, Triumph may be spent to add an additional effect (no greater than one difficulty level per Triumph) to the scroll. Threat typically means that the scroll takes longer to complete; Despair could mean that the prepared spell goes off when you complete the scroll!

The spell bound within a scroll may be cast by anyone. It takes one action to cast a spell from a scroll, and requires either the appropriate magic skill (depending on the nature of the scroll), or a Knowledge: Lore check. The difficulty is the same as that of the spell contained within the scroll. Casting a spell from a scroll is not considered a magic action, and does not cost 2 strain. Regardless of whether the character using the scroll possesses the appropriate magic skill or not, no additional effects or difficulty reductions may be applied to the spell cast from the scroll.