While official studio acapellas are often distributed privately as "stems" by record labels, you can find high-quality DIY and cover versions across several platforms:
How to get PERFECT Acapellas & Instrumentals (Studio Quality)
To ensure your mix sounds professional, keep these technical details in mind: 124 BPM. Key: A Minor (Am). Vocal Range: G3 to E5. Where to Find the Acapella
Finding a clean acapella for Calvin Harris and Rihanna ’s massive 2016 hit, is a top priority for DJs looking to create energetic mashups or house remixes. With its steady 124 BPM and recognizable vocals, it’s a perfect tool for the dance floor. Essential Track Info for DJs