Help Email account question

This may be a dumb question but I couldn't find the setting in this phone. I have my work/enterprise account on the phone, and currently, when I delete an email on my phone, it also deletes it in outlook on my work computer. Is there any setting available where I can delete something on the phone without it deleting on the computer? I like to keep my phone clear of email unless I really need them on the go.

Also, is there a setting for how long I can keep the email in my phone? Does it disappear after a certain time?

I came over from a blackberry and the email was pretty easy to figure out but it's different here.

Thanks a lot!