What is a guest profile?
A record of one person: their name, contact details, country, ID number and any notes you have kept. It is created the first time they stay and reused every time after.
You do not build this database deliberately — it accumulates. Every booking you take and every OTA reservation that arrives adds to it. After a season you have a real picture of who stays with you.
Profiles belong to your property. Nothing is shared with other hotels.