How to switch from offline to online in MS outlook?

MS outlook is an amazing feature-rich desktop email service, which is mainly used by many users. This emailing application is the best tool for sending and receiving emails, but it can be very frustrating when it goes offline mode. I am facing offline mode problems in MS outlook. I don’t have knowledge to switch from working offline to working online in outlook. I am applying my skills to resolve this offline mode problem. So anyone can recommend the easy tips to resolve this problem easily.