D&B
EASA means all aircraft parts require a form one regardless of where the registration is obtained.
Box 13 is dedicated to new parts manufactured under part 21.
Box 14 is the part 145 crs statement
You cross out what box (13 or 14) that is not applicable to the part.
Young engineers do not accept a part that has no certification unless it has the exception of being internally robbed from your own companies aircraft under your own 145 approval. Even then check effectivity, ETOPS compliant etc.