From LimeSurvey Manual
- Send email invitations: Send email invitations to the selected survey participants;
- Send email reminder: Send email reminders to the selected survey participants;
- Add participants to central database: In the case in which you would like to use some of the token entries into another survey, add the selected participants to the central participant database. From there, you have the option to add the participants to any survey you wish. For more details, continue reading the Share this participant wiki page.