If you’re an iPhone user, check your storage now by selecting Settings, then General and then iPhone Storage.
You’ll probably see a lot of recognisable categories eating up your storage — apps, photos, and so on. But there is one, often rather large category, that may raise concerns: “Other”.
It’s shaded light grey and often represents a significant proportion of the overall storage available.
What is ‘Other’?
For more detail, scroll down and tap the “Other” category (right at the end).