Select FILE > New > Project.. > Qt5 Projects > Qt Application > Next > Next > Finish > BUILD > Build solution
Error 2 error LNK1112: module machine type 'x64' conflicts with target machine type 'X86'
Workaround is to manually change target platform to x64 and also have to reselect correct Qt version. Right click Solution > 'Change Solution's Qt Version'. Then building success.
It's expected that Qt wizard would automatically select x64 to default platform if Qt used version is 64-bit.