64-bit apps

Yes. Microsoft Office 2016 apps can be updated to 64bit, and Microsoft Office 2018 apps and Office 365 subscription Apps are 64 bit natively.

See here: https://support.microsoft.com/en-us/help/3187505/office-2016-for-mac-64-bit-upgrade

and here: https://products.office.com/en-US/compare-all-microsoft-office-products?&activetab=tab%3aprimaryr1

I use Office 365 (Excel, Word, Powerpoint) and it's 64-bit

Ask Microsoft for it.

Excel is their product.

Or you can switch to LibreOffice instead. It is free.