The guides for sentient item creation and artifact creation mention nothing on attunement, but all of the sample items require it. However, the rules for custom magic items on DMG 284-5 do mention attunement. All they have to give is general advice.
Can you attune to a magic item?
Yes, an unattuned magic weapon can be a pact weapon. Some magic items require a creature to form a bond with them before their magical properties can be used.
Do magic shields require attunement?
Some magic items require a creature to form a bond with them before their magical properties can be used. For example, a magic shield that requires attunement provides the benefits of a normal shield to a creature not attuned to it, but none of its magical properties.
What does it mean to be attuned to magical items?
Think of attunement as “unlocking” the magical abilities of certain magic items. These items require your character to form a bond with them (i.e. attuning to them) to work. Some items may have certain prerequisites or requirements to be attuned with.
How many magic items can a creature attune to?
An item can be attuned to only one creature at a time, and a creature can be attuned to no more than three magic items at a time. Any attempt to attune to a fourth item fails; the creature must end its attunement to an item first. Additionally, a creature can’t attune to more than one copy of an item.
Do you have to attune items in 5e?
An item only requires attunement if it says it does. This might sound obvious, but a good selection of 5E’s items don’t require attunement. For example, a +1 War Pick doesn’t require attunement. However, the Will of the Talon artifact does. Make sure you and your DM both know what items require attunement before wasting a short rest on something…
Can you use a short rest to attune to a magic item?
Thus requiring only one short rest. No. You can’t attune to a magic item if you don’t understand it’s properties, especially if you don’t know that it requires attunement. The rules specifically require that the short rest used to attune be a different short rest than the short rest used to identify its properties:
