First you have to check if the POP is supported by your email provider and if so, you must know the POP configurations like Outgoing server address, Incoming server address, ports etc. If you don't familiar with them, please contact your email provider for further assistance, thanks.
Moreover, if your email account supports POP, in this case you can try to manually configure your email account as POP into Outlook Client. For your reference Manually configure Outlook emails .
On another hand, since the category in this forum is dedicated for Outlook Customer Manager ( OCM), so if your issue persists, please post a new thread on Office Support Forum > Office category, the dediated support engineer there would give you more assistance regarding your problem, thanks.