Hi Harlow0105,
If you don't see the email that you sent on your iPhone, try opening a web browser and checking your email via the web portal to see if you can locate your sent email or if it is still missing there.
Also, did you accidentally schedule the email to be sent later? If you're not sure, follow the steps in the link below.
Send email in Mail on iPhone - Apple Support
To perform the recommended troubleshooting steps via the link above, complete the steps in the section titled "Schedule an email with Send Later."
Touch and hold
, then choose when you want to send the email.
To see more options, tap Send Later.
We're recommending the steps above because they directly address the issue you initially posted about: you're unable to locate an email you sent from your iPhone.
Please let us know what you find after giving the above steps a try.
Thanks for using the Apple Support Communities.
Cheers!