The internet's address book: it turns a name like yourbusiness.ca into the numbers computers use to find it.
Like the directory at a mall entrance: you look up the shop name and it tells you which door to walk to.
A four-person consulting firm switched website hosts and the designer changed the nameservers. The old MX record vanished with them. Email stopped arriving for two days, and nobody noticed until a client called to ask why a signed contract had bounced.
Domain Security covers DNS, registration and protection: it holds the records, keeps the registration from quietly expiring, and watches for hijacking or spoofing. Changes go through WILDCARD, so a web designer cannot knock the email offline by accident.
Example scenario: A two-person bookkeeping firm found their website showing a parked page one Monday. Their domain had expired over the weekend because the renewal notice went to an old address. Recovering it took a redemption fee and three days of lost email. A watched registration would have renewed it quietly a month earlier.
Do I need to understand DNS to run my business?
No. You need someone who does, and you need to know who is allowed to change it. Keep DNS with one trusted party and ask before any designer or vendor touches it.
Every WILDCARD card exists to solve one named problem. Find yours.