Why is the referral code filled and greyed out while registering in Binance

Good day, I decided to dive into the cryptocurrency world, upon registering I found out that under the email and pass there is a referral code that is greyed out, can't delete it nor change it.

I used binance.com, not any other link. The laptop is personal and it's my first time creating an account. Anyone can explain what is happening, as I searched it up on google with no results.