I am trying to read emails from my O365 mailbox through a windows forms application. I want my application to read emails from O365 mailbox using my username and password. Is it
Yes, you can do with with Exchange web service API. It is designed for client application. Follow the link, you can find a lot of examples.
One note is: to create the service client, you need specify the version of the Exchange Server, it should be ExchangeVersion.Exchange2013_SP1
for exchange online.
ExchangeService service = new ExchangeService(ExchangeVersion.Exchange2013_SP1);