Which Timezone to show the user?

Our application runs on servers that might sit in another country. They will process money transfers from banks and each transfer might origin by a different user from a different country. The transaction will gather rules, audits, notes, and other information along the way, and each will have its date and time.

I have a problem deciding which timezone to show the user.

The back end (processing information) will be kept in UTC to make everything simple, but is it common to display UTC to users?

Also, we have multiple dates and date&time fields on our forms (for example: create date&time, processing date&time, settlement date&time, credit date, debit date...)

Should we translate the date&time to the user timezone always? Should we show UTC?

Any help will be great, Thanks