My phone is off due to a low balance & i can't text anyone when i pay my bill will they receive that text or will i have to send it again?

I thought on iPhone as long as you around Wi-Fi you can text or talk

If you're on Wi-Fi you should be able to use iMessage if you're logged into iMessage with an Apple ID. Also, if you're logged into Facetime with an Apple ID you should be able to Facetime or Facetime Audio people.