Quick question: How do I change to 64 bit?

I got the same question few days ago.

To solve this issue I had to :

   1. Open the Android Player Settings

   2. Open the Other Settings category

   3. Select IL2CPP scripting backend

   4. Check ARMv64 in the Target Architectures

   5. Check Split APKs by target architecture (optional, but your players won't have to download a huge archive with 2 useless APKs). Then, in Google Play, you will have to upload 3 APKs instead of 1.