Original Text at bottom, just wanted to try to reformat it as English native speaker (Thank you so much for this excellent guide, Andres B. Tomasini!!!) Have only commented here a time or two so I'm sorry if I mess this up.

To play ONLINE with SmartSteamEmu - (You do NOT need Steam to play) -

1. Go to the RE6 game directory, delete all .ini and .txt files EXCEPT origin.ini.
2. Go to the SSE v.1.4.3 folder, located in: >RE6GameDirectory/NoDVD.
3. Open SmartSteamEmu.ini and find the line: Persist= 0
4. Change: Persist=0 to: Persist=1
5. Run SmartSteamLoader.exe AS ADMINISTRATOR
6. In game, complete the prologue then in the Menu, select Play>Campaign or Extra>Join Game or Create Session.
(OR you can open the SmartSteamEmu overlay by pressing SHIFT+TAB, where you can view all players and join sessions.)

Original Post:

Andres B. Tomasini • a day ago
For play ONLINE in SSE(not need Steam for play) go to directory of RE6 delete all files .ini and .txt less origin.ini,and later copy and paste in game directory all content of SSE_v1.4.3 folder,located in game directory\NoDVD,Open SmartSteamEmu.ini and find line Persist = 0 change 0 for 1(Persist = 1).Run SmartSteamLoader.exe WITH ADMINISTRADOR!.In the game complete the prologue,later in the menu go to Play\Campaing or Extra\Join Game Or Create Session\Or open SSE overlay press SHIFT + TAB,you can view all players,invite and join in sessions.

For play OFFLINE connect 2 or more pc in network wifi or lan cable(not need internet)and follow all steps up
Tested offline in 2 pc its works! ;)