Below are the formal and polite equivalents (synonyms) of 'ask about' which you can use in your business or professional pieces of writing.
The below synonyms are used when you want somebody to give you some information about a thing or a person. You wouldn't use these if you are asking somebody to do something for you or to give you an object/thing (like a book, a report, a pen etc...). To do these types of things, see the synonyms in 'ask for'.
A formal way to say 'ask about'.
'I would like to enquire about the changes to company policy on returns.'
'She enquired about how you have been doing since you started with us.'
This is a different way of saying 'enquire'.
'Last week I made an enquiry about taking out a new loan with your bank.'