When you get a new iPhone should you charge it fully up?

Elias-mitsopoulos wrote:

When you get a new iphone should you charge it fully up, and use it till its dead, or use the remaining battery thats on till its dead? Please help me

See this wonderful article:

When to charge your iPhone or iPad - Apple Community

You do not want to let the battery drain completely. You may charge the battery at any time for any amount of time. I keep my phone and iPad plugged in every night so I have a full charge in the morning. You cannot over charge a phone or iPad.

You can charge it, you can use it. But never allow your phone to discharge to 0%. It kills the battery and it will age faster.