Which expression of thanks is more formal?
We're so pleased you could join us on our special day. Thank you again for the wonderful gift. We're super happy that you could be with us on our special day. Thanks again for the awesome gift!
Informal writing is typically used in casual situations or when communicating with someone you know well. Informal language often expresses familiarity and tends to sound more like speech. It uses more conversational language, such as slang, idioms, abbreviations, imprecise language, and contractions.
Formal writing is typically used in academic and business writing or when writing directly to an authority figure. It tends to be more courteous and impersonal, avoiding overly familiar or conversational language.
Compare the following sentences.
Informal: Yeah, ostriches can't fly, but I think they're awesome.
More formal: Ostriches may be flightless, but they're remarkable runners.
Most formal: Though flightless, ostriches are remarkable runners.
The second expression of thanks is more formal. It uses more elevated language (we're so pleased). The other expression of thanks is more conversational (super happy, thanks, awesome).