Hi Mark,
This isn't recommended as any user can then use the token to access any part of your organization, data, users, functionality as you. This could potentially be a large security hole.
If you are looking to share your application, consider sharing the application publicly or creating a group and sharing the app, data and web map only with the group of users that should access it. They will require an ArcGIS Online account in order to use this security method.
Here is a link to some developer Authentication help:
Get an access token | ArcGIS for Developers
https://community.esri.com/community/gis/web-gis/web-appbuilder?sr=search&searchId=28c29a76-9158-4ee...
-Kelly