The first member of the Trinity is referred to as the Father throughout the New Testament. However, while we might expect the usages to be fairly uniform from book to book, they are not.
There are less than ten uses in most of the books of the New Testament.
Luke and 1 John have over 25 uses each.
Matthew has just under 100 uses of Father. That may seem like a lot. Yet Matthew uses the Father about one-third as often as John.
John’s Gospel uses the term Father a whopping 250 times!
It should be noted that uses per chapter in John and First John are similar. John’s Gospel has about twelve uses per chapter. First John has about eight uses per chapter. No other books in the New Testament have such high per chapter uses of Father.
The reason might be that John’s Gospel is evangelistic and 1 John is about fellowship with God. For both themes the relationship between God the Father and God the Son are vital. We can only have everlasting life because the Son carried out the will of the Father. We can only walk in fellowship with God because the Son shows us the Father and the more we gaze upon the Son, the more we are transformed into His likeness. And of course our abiding in Christ is akin to the Son’s abiding in the Father.