Windows 10 64-bit with Office 365 32-bit
Microsoft recommends the 32-bit adaptation of Office 365, even if you have 64-bit Windows.
A 64-bit operating regularity is capable of using sizeable amounts of memory – much more than you could cram into your computer even if you used a toilet plunger. Your Office 365 files are very unlikely to need that much memory.
On the other hand, many of the components and add-ins that people use with Office 365 are 32-bit software.
For the uber-geek details,
here is Microsoft’s explanation of it. It will make you sorry that you asked in the first place.
Just keep in mind: 64-bits is not ‘better’ than 32-bits; it just means it can accommodate more RAM. Or to put it another way: If a 5-Cycle BMW is big enough for you then you won’t gain anything by trading in for a 7-Cycle. Am I getting my point across?