Purpose was met with generally positive reviews from music critics and debuted at number two in South Korea, selling over 154,258 copies.

[6] Meanwhile, "Here I Am" is a melancholy ballad song that characterizes the sensation of feeling trapped in a sense of loss following a breakup, expressed through one's self-image reflected in a mirror, thus eliciting a powerful vocal performance from Taeyeon,[7] along with "Gravity", another pop ballad song featuring an impressive, soulful melody that metaphorically compares constant love to a gravitational force and expresses gratitude towards an unwavering heart.

[8][9] "Do You Love Me" is a jazz-based ballad song that combines musical instruments and vintage string sounds reminiscent of a jazz club, starting with a piano and a confessing voice about a hidden love, while "Better Babe" is a blues-rock track that articulates the sorrow and anguish following a break-up, with Taeyeon's soulful voice conveying emotion initially, building up to a powerful crescendo by the chorus.

[14] "My Tragedy" is a trip hop that starts with the sound of a reed organ, leads to an orchestral arrangement, and symbolically depicts the profound sorrow of a shattered love by likening it to a lunar eclipse in its lyrics.

Chester Chin from The Star lauded the album's musical styles with "the artistic confidence on Purpose feels intensely liberating, and it is one heck of a confident record – in soul, sentiment and sound" and "On Purpose, the Girls' Generation alumni delivers a larger-than-life performance on a deliciously darker and much more musically complex record".

[35] On October 14, 2019, Taeyeon released teaser photos for the album featuring a "red-lit aesthetic" of her face and shoulders,[1] which was called "sultry" by Gulf News.

[36] SM originally set the release date of the album on October 22, 2019, but the promotional schedule was temporarily halted due to the death of Sulli.

[40] Taeyeon did not appear on any music shows and or engage in any promotion for Purpose (except for fansign events) as she decided to pay respects to her late friend Sulli, and also to take care of her mental health.