As stated in RAD Studio docwiki, to migrate 32 bit VCL application to 64 bit:
Open your 32-bit application in the IDE, add and activate the 64-bit target platform, and compile your application as a 64-bit application.
I have a project group that contain more than 200 32-bits projects. In order to support 64 bits, I need to add the 64 bit target platform one by one.
Is there a faster way to add 64 bit target platform ?