If you want the full version and license for commercial use,
you can purchase here :

https://fontkong.com/product/massmellow/

File Font Version : 

1. Massmellow.otf
2. Massmellow.ttf
3. Massmellow.woff
4. Massmellow Swash.otf
5. Massmellow Swash.ttf
6. Massmellow Swash.woff