PPPoE stands for Point-to-Point Protocol over Ethernet. It is a network protocol sometimes used by broadband modems for DSL Internet service.
PPPoE allows Internet Service Providers to manage access to accounts via user names and passwords. The username and password is often configured in the DSL modem or router itself and does not require any additional software configuration.
Another distinct characteristic of PPPoE connections is the fact that packets must account for an additional 8-byte PPPoE header, making the maximum packet size 1492, as opposed to 1500.
If you configured PPPoE Dialer in your PC or Wifi Router you will get internet without asking login page. For that we need to configure our IP and password in our device 1 time it will connect automatic to internet.
Please check this link for configure PPPoE in PC https://www.home-network-help.com/pppoe-dialer-setup.html
Please check this link for configure PPPoE In D link Wifi Router https://kb.nex-tech.com/article.php?id=152