"Everything Has Changed" peaked at number 32 on the US Billboard Hot 100 and was certified double platinum by the Recording Industry Association of America (RIAA).

[13][14] The track extensively uses syncopation at the sixteenth-note level, which musicologist James E. Perone deemed a trademark style of Swift's music and reminiscent of her self-titled debut album (2006).

[15] On June 8, 2013, Swift and Sheeran performed the song on the season finale of the seventh series of Britain's Got Talent.

[25] The Recording Industry Association of America (RIAA) certified the song double platinum for surpassing two million units based on sales and streaming.

[8] Mesfin Fekadu of the Associated Press considered "Everything Has Changed" a highlight on Red, praising Swift and Sheeran's falsetto vocals.

[36] In the Los Angeles Times, Randall Roberts called it a "powerful collaboration" and picked it as one of the album's "well-constructed pop songs Taylor-made for bedroom duets".

[38] Jon Caramanica from The New York Times considered Swift's songwriting on "Everything Has Changed" not as strong as on her past songs, but still maintained "her ear for the awkward and tentative rhythms of romantic bonding".

[13] Sian Rowe, a writer from NME was upright critical, deeming it inferior to respective singer-songwriters' material and "disappointing in every way".

[40] Tony Clayton-Lea from The Irish Times deemed the track Swift's "desperate attempt" to reach out to new audiences.

[41] Also from The Irish Times, Eoin Butler gave the single a two-out-of-five rating, calling it a "typically slushy ballad".

The video begins with two children who initially appear to be Swift and Sheeran when they were much younger, meeting each other on a bus to elementary school.

[49] At the end, Swift and Sheeran appear and are revealed to actually be the parents of their child counterparts, arriving at the school to pick them up and take them back to their respective homes.

[71] Prior to the release, on August 23, 2021, Sheeran shared a clip on social media showing him in the studio, re-recording the track and another collaboration with Swift for Red (Taylor's Version) titled "Run".