Can I use my iPhone while charging?

It's safe to use the phone while charging. It will slow the charging rate slightly, as the energy from the power source goes to operate the phone, and the battery is charged with whatever is left. Here's my user tip on battery management-->When to charge your iPhone or iPad - Apple Community and here's Apple's-->iPhone Battery and Performance - Apple Support.

I think mine is better 😀

You can use it while charging, it is safe and it does not affect the battery. If you are doing something that is processor intensive it might slow the charging a little.

There is no problem if you do it for not very long, but if it becomes hotter or it is very cold in the room I recommend you to first charge your device.

the battery is designed to be charged and drained, it also has a limited time to work (~3-5 years) if the battery drains too quick it might be because it is already too old or it was often used while being hot. Therefore if you feel that your device becomes hot and you continue to use it your battery might loose some of it’s capacity forever.

But it is safe to use it while charging and won’t lose capacity.

Wish you all the best

Nick Inge

You might want to read Mr. Finch's battery article link in the post above yours.