You could say those particular words are written in title case to indicate it’s an acronym.
Title case (capital case, headline style)
"The Quick Brown Fox Jumps over the Lazy Dog"
A mixed-case style with all words capitalised, except for certain subsets (particularly articles and short prepositions and conjunctions) defined by rules that are not universally standardised. The standardisation is only at the level of house styles and individual style manuals.
However, I’d prefer to write the phrase in long form the first time it was used, followed by its acronym in brackets, and then use the acronym from there on in the document.