Hello dnlyko, I hope you are well. You can always use Web-Based Email to send and receive email messages. But you also can view your email with an email client.
You can change to IMAP by changing your existing account or by creating a new one from within your email client. You cannot change the account type for some clients, including Apple Mail, Outlook 2010, Outlook 2013, Outlook 2016 and Thunderbird®. To use IMAP with these clients, you must create a new account.