The capitalization of "Be F o Ur " is a play on words. When Zayn left One Direction, the group was left with exactly four members. Additionally, Four was the name of the last One Direction album Zayn was a part of.
Musically, the song features a standout high-reaching falsetto run during the middle eight section, which served to distinguish his solo R&B sound from his previous pop work. ZAYN - BeFoUr
In the second verse, he sings, "No strings for you to pull on," which fans and critics see as an allusion to feeling like a puppet or being manipulated during his time in the band. The capitalization of "Be F o Ur " is a play on words