I sometimes see "safe the date" on webpages. I always thought it was "save the date" as in "saving the date to a calendar". Also, there is no verb safe.
Using "safe the date" feels wrong to me.
And, is "save the date" a phrase that is commonly used or is there a better phrase?
AFAIK it means something like "please save the date to your calendar (or remember the date and block it)".