How to make sure that emails are NOT deleted from server


New Email
Hi all

Just a quick question on behalf of my mum please. She uses Mac Mail on her desktop but sometimes also uses the Yahoo webmail (if that is the correct term) on her Chromebook.

She would like to set it up so that, when she accesses emails on her computer in Mac Mail, those emails still remain on her Yahoo webmail. Currently, any email she accesses on her computer is automatically deleted from Yahoo webmail. I can't find any settings that relate to this. (On my own Virgin webmail, there is a simple setting for this.)

Please can anyone help -it's extremely frustrating. Thanks in advance.