Avoid Using a Case When Charging
It’s best to avoid using a case on your iPhone when you’re charging it, but that doesn’t apply to every case. So how can you tell you need to take your iPhone out of its case? It all depends on your iPhone’s temperature while charging.
If your iPhone gets very hot when it’s charging and the ambient temperature isn’t necessarily high, you might want to take your iPhone out of its case.
Your iPhone doesn’t like high temperatures, especially when charging, so avoid using the case if that’s what’s making it get hotter. Again, not every case will give you this problem. For instance, if you’re using a first-party case, or a ventilated one, your iPhone shouldn’t give you any trouble.