To the OP: Suggest to Start by learning about PFC, a huge topic.
PFC measurement, requirements and solutions are very well know, please consult the many books and papers and seminars on PFC, eg IEEE, PESC, PELS,
An old colleague Dr REDL is a world expert and has dozens of fine papers and seminars.
EU and other Customs now can block entry of non-compliant products, or even require proof of testing.
If your firm is going to manufacture an industrial product, you should purchase all applicable standards for EMI, PFC, transient, safety.
Search your market areas (where it shall be sold) for the requirements.
Most USA/CA/EU standards are harmonized, so IEC, CISPR, UL, will be interchangeable.
Using partial free excerpts off the Web is risky.
The PFC harmonics requirements will apply to a 400 W device, and normally a PFC prestage is needed.
Many off the shelf solutions are possible.
Beware that any SMPS or PFC generate EMI conducted and radiated,
Compliance with EMI, also transient susceptibility is applicable.
Bon Chance,
Jon