Translation guide
Facebook is a social media platform. In Japanese, it is usually referred to by its English name, written in katakana.
Referring to the Facebook website or app
The standard Japanese name for Facebook. Used in all contexts.
フェイスブックで友達と連絡を取っています。
I keep in touch with friends on Facebook.
フェイスブックのアカウントを持っていますか？
Do you have a Facebook account?
An abbreviation sometimes used in casual online communication, similar to English.
FBでイベントの招待を送ったよ。
I sent you an event invite on FB.