Yes, the 'if' clause has been placed at the end of the sentence, rather than at the start. A more familiar order of words would be something like:
- If you hold English and Chinese proficiency certificates, then those documents are required.
In the document that your question links to, #7 is one element of a list of "Required Documents". The entries in the list are (sets of) nouns and noun phrases. The inverted word order allows entry #7 to start with the relevant nouns and noun phrases.
Note that each entry in the list is worded as a bullet point, not a complete sentence in the traditional sense. The phrase "if holding" doesn't make #7 grammatically correct as a complete sentence, but it does act as a qualifier for the noun phrase at its head. Note also that even as a qualifier for the noun phrase, the continuous tense sounds a little awkward to me. I'd have preferred the simple past tense: "..., if held", or "..., if attained".