There are countless ways to write dates. It really depends on the type of writing and its purpose:
This is the typical format for labeling an essay or professional letter:
February 25, 1987
25 February 1987
In the text of formal writing:
On February the twenty-fifth...
In February 1987...
On February 25th...
This is a more informal way to write dates:
In a story that includes dialogue, dates and numbers are typically spelled out:
The two girls were talking on the phone.
"When were you born," she asked her friend.
The friend enthusiastically replied, "February twenty-fifth nineteen eighty-seven."