Microsot office

if it's office 2011 then it's because it's a 32bit app and not supported by microsoft anymore

your options are

1. downgrade to mojave
2. use a free ms office compatible office suit like LibreOffice
3. rent microsofts office 365 suite
4. purchase microsofts office 2019

Your documents created by Office 2008/2011 for Mac are unaffected by the 64-bit application requirement on Catalina. Once you follow Rudegar's advice (other than step 1), then the documents will be accessible again.