[HarryStamper]

I have an iPhone 4S and an iPad 4th generation. Now, I just went on my iPhone and removed several emails,
A few minutes later, I went into the mail app on the iPad and those same emails were there.
The email account is a pop 3. I know that a Yahoo mail account would remove them right away...and they would not be visible on the iPad.
Because the mail account is a pop 3 that's why I have to delete the same emails from both devices?

[Karenkcoulter]

Probably.

[Fausty82]

I have an iPhone 4S and an iPad 4th generation. Now, I just went on my iPhone and removed several emails,
A few minutes later, I went into the mail app on the iPad and those same emails were there.
The email account is a pop 3. I know that a Yahoo mail account would remove them right away...and they would not be visible on the iPad.
Because the mail account is a pop 3 that's why I have to delete the same emails from both devices?

Yes.

POP email accounts download copies of emails to each device. Once it’s removed from the server, it’s gone... but if it’s still on the server, when you check mail, you get everything that you have not previously received on that device. Deleting the message(s) from your iPad won’t remove them from the iPhone, and vice versa.

IMAP mail provides you with a view of the server mail... so whatever you do on any device, the effect is seen on all other devices that access that mail account. So deleting it on the iPad will cause it to be removed from the view on the iPhone (and vice versa).

Hotmail does use IMAP... other mail services offer different choices and what happens depends on which choice you implement.

[HarryStamper]

Thanks for confirming.