You need an embassy visa for Puerto Rico if you have a Ukrainian passport
Visa options for Puerto Rico
Visitor visa
Travellers need a visa to visit Puerto Rico for Business or Tourism. A paper or embassy visa is the only visa available for travellers visiting Puerto Rico. The visa is typically a stamp or sticker added to the passport. Travellers must obtain this visa from a local embassy, consulate or visa center before travelling. Ukrainian citizens and their family members can enter the Puerto Rico and stay temporarily for 2 years of parole.
This is not offered by sherpa°.
Apply on the government site.