By default, iManage plugin embedded in Foxit Editor only supports explicit login(username and password). In Version 12 and higher version, it also supports SSO login. After enable SSO login in iManage portal, please follow below steps to make Foxit client compatible this login method.
1.Open Registry Editor > Navigate to HKEY_CURRENT_USER\SOFTWARE\Foxit Software\Foxit PDF Editor 12.0\plugins\iManage10 > Create new key "loginMethod" , create new DWORD value (Name : UseOAuth2 ； Type: REG_DWORD ； Data:00000001 1 means login with OAuth2)
Best Practice —How to apply the registry value to all users?
Foxit Customization Wizard tool support to create registry data. You could use it to create registry like below picture then generate the .mst file 
Apply the .mst file during installing the client.
After finish the installation , you will see the folder generated in registry editor.
For more details, please refer to below links :
- get Customization Wizard: Available Foxit Customization Wizard Tools for Foxit PDF Editor for Windows version – Help Center | Foxit Software
- How to use this tool: Generate transform MST files via Customization Wizard – Help Center | Foxit Software
2. Configuring Foxit Application in iManageCC . 
The parameters to be filled in the configuration are as follows:
- Client ID = API key = 71520fcb-5898-4adf-97fc-87e4bc4b6ef9
- Client Secret = API Secret = aa4e280a-0fd8-46c2-a8eb-2320905363a4
- Application Type = (Checkbox)Native
- Redirect URL = http://localhost/
- Allow Refresh Token = (Turn On)Yes
For more details, please see below video:
