You can but it depends on how you use the email first.
There is currently no option to import from regular webmail from the website.
If you have a email client such as outlook there is an import tool to do that. You can find that here : https://support.office.com/en-ie/articl ... 04b9c44bf7
I believe other email clients do this as well and a google search should bring up how to do that.