If they get priority in the name they get the suffix 'al' or 'carbaldehyde' As substituent prefixes 'oxo' and 'formyl' are used. The prefix 'formyl' is used in preferred IUPAC names, except for a -CHO group at the end of an acyclic chain.

Where is oxo used?

If a prefix form is required, “oxo-” is used (as for ketones), with the position number indicating the end of a chain: CHOCH₂COOH is 3-oxopropanoic acid.

What is the difference between formyl and aldehyde?

is that aldehyde is (organic chemistry) any of a large class of reactive organic compounds (r ·cho) having a carbonyl functional group attached to one hydrocarbon radical and a hydrogen atom while formyl is (organic chemistry) the univalent radical -cho, derived from formaldehyde, that is characteristic of aldehydes.