How to add feedback seekers/participants for the survey?

The only way to add feedback seekers is to add the users to the group in "Manage Groups". You can learn about adding users to a group in the article "How to add participant(s)/ user(s) in a group?/ How to enroll participants for a content?"

However, any user in the account mentioned in "User Management" can be a respondent. If a user has not been added to the account, they can be added through the process mentioned in "How to add/remove respondents in a feedback survey?". You can learn more about "User Management" in "How to upload new user(s) in User Management?"