Looking on the internet deeply has found these results:

in an email is the most popular phrase on the web.

on an email 164,500,000 results on the web	in an email 1151,000,000 results on the web More popular!
Some examples and use cases from the internet:	Some examples and use cases from the internet:
I've just spotted new activity on an old email account that Morris had before he went to prison. based resource, but several judges expressed a preference for paper versions. Its. I got an email on my phone. This has been confirmed by information submitted in an email on 1 June 2012 (Event No 636529) from the Icelandic authorities. All right, from now on I'll email an agenda in advance. The main focus was on an email Last week he CC'd me on an email to Jerry complaining that I ordered too many rainbow Post	And Chris had said in an email that, you know, we should really bring something new to TED, something that we haven't shown anyone. This has been confirmed by information submitted in an email on 1 June 2012 (Event No 636529) from the Icelandic authorities. In an email to the station, El Hazim has claimed... You wrote it in an email! Never put anything in an email you cannot own. Manning did reach out for help at least once, in an email to his master sergeant. It's not necessarily the actual words that someone has written in an email or given on a phone call.

on an email

164,500,000 results on the web

in an email

1151,000,000 results on the web

More popular!

I've just spotted new activity on an old email account that Morris had before he went to prison.
based resource, but several judges expressed a preference for paper versions.
Its.
I got an email on my phone.
This has been confirmed by information submitted in an email on 1 June 2012 (Event No 636529) from the Icelandic authorities.
All right, from now on I'll email an agenda in advance.
The main focus was on an email
Last week he CC'd me on an email to Jerry complaining that I ordered too many rainbow Post

And Chris had said in an email that, you know, we should really bring something new to TED, something that we haven't shown anyone.
This has been confirmed by information submitted in an email on 1 June 2012 (Event No 636529) from the Icelandic authorities.
In an email to the station, El
Hazim has claimed...
You wrote it in an email!
Never put anything in an email you cannot own.
Manning did reach out for help at least once, in an email to his master sergeant.
It's not necessarily the actual words that someone has written in an email or given on a phone call.