How to change settings to leave email on my website's server

Can anyone help?

A couple of years ago I set up my emails to be forwarded to Outlook (for ease of use) At the time, I thought it would be better to not clog up my website's server with emails, so opted to have them NOT be left on my website's server but just forwarded.

Having just had a problem with Outlook - I think it might be prudent to also have a copy of the email left on my website's email account.

But...I can't remember how to access the settings for the email - is this something that I need to do on Outlook? (I can't find where) - I have read elsewhere that I need to click on 'File' - but I can't see a File tab in Outlook.

Anyone able to help?