hi.
LP uses the default WP user profile for LP users, so it actually uses the same table to store data (ie all new users are added to this table). This means the table fields for wp_users are fixed (cant add extra fields). However, you can have another table that stores the extra fields (most custom form generation plugins do this). This extra table needs to be linked to the wp_users table through a key (unique identifier in the new table that relates to the wp_user row / user). This basically tells the new table that the data in row ‘x’ belongs to user ‘y’ from the wp_users table.
Now that we have the technical garble out of the way, the short story is this: You can use a custom registration plugin like “Ultimate Member” or “Registration Magic” which have the option to create custom user registration forms that store user data in wp_users and a custom table. You can access the custom fields from this new custom table using available functions from these plugins (e.g. if you use Ultimate member, you can use the custom function “um_user()” to display the user data. You may also view the data directly using phpmyadmin. Hope this helps
Goodluck!