Is it ok to use the iphone while it is charging?

I was just wondering if it is safe to use the iphone while charging or could it affect the batterie lifespan

No, it is not OK.

Yes. The iPhone has Lithium based battery so, it has no memory so it doesn't effect the battery.

I always do and nothing bad has happened

Yes it is, I use it all the time while it is charging. If it does it must be really minor