Where does the Entity Registration module store the signup data and how to delete it?
Where does Entity Registration store the signup data?


Looking at the module's .install file, those data should be stored in  the table with name registration. Especially these columns of it should be close to what you're looking for:

  'count' =&gt; array(
    'description' =&gt; 'How many spaces this registration should use towards the total capacity for this event.',
    'type' =&gt; 'int',
    'not null' =&gt; TRUE,
    'default' =&gt; 1,
  ),
  'user_uid' =&gt; array(
    'description' =&gt; 'The uid of the user associated with this registration.',
    'type' =&gt; 'int',
    'not null' =&gt; FALSE,
    'default' =&gt; 0,
  ),
  'author_uid' =&gt; array(
    'description' =&gt; 'The uid of the user who created this registration.',
    'type' =&gt; 'int',
    'not null' =&gt; TRUE,
    'default' =&gt; 0,
  ),
  'state' =&gt; array(
    'description' =&gt; 'The {registration_state}.name of this registration.',
    'type' =&gt; 'varchar',
    'length' =&gt; 32,
    'not null' =&gt; TRUE,
    'default' =&gt; '',
  ),
  'created' =&gt; array(
    'description' =&gt; 'The Unix timestamp when the registration was created.',
    'type' =&gt; 'int',
    'not null' =&gt; TRUE,
    'default' =&gt; 0,
  ),
  'updated' =&gt; array(
    'description' =&gt; 'The Unix timestamp when the registration was most recently saved.',
    'type' =&gt; 'int',
    'not null' =&gt; TRUE,
    'default' =&gt; 0,



  How do I see the information collected?


Option 1: Just browse this table, using your preferred tool to do so.

Option 2: Use the Views module to create an appropriate view of it, as suggested also in its community documentation, i.e.: "Not happy with the default tabular list of registrations? No problem, registrations and their fields are all Views friendly. You can override the default event registrations list, create additional ones, etc". You probably want to enable its registration_views submodule for this.


  How do I delete it?


It may be straight forward to just delete the relevant rows in the "registration" table mentioned above. However because of its integration with the Rules module, I'd rather use this module, possibly combined with the Views Bulk Operations module, to perform such deletes