I want to be able to change the format, background colour and font, of
a cell dependent on the manually entered content of that cell.  I am
aware of Conditional Formatting, but this only gives me three options,
whereas I need three groups of three, i.e. if contents = A or B or C,
apply format 1, if contents + D or E or F apply format 2 etc, otherwise
leave as is.

Can I make this work using the built in CF function?  If so how?

Or do can I do this via a formula?  If so how?

I've not got much experience of this aspect of Excel, so any help
offered would be gratefully received.