For most of the databases, monthly PPP data is not provided. How it can be possible to find monthly PPP data? i mean PPP(exchange rate) conversion factors. Thanks
I don't think that there is a monthly PPP series but you might want to contact the OECD as they have a monthly comparative price levels(https://www.oecd-ilibrary.org/economics/data/prices/comparative-price-levels_data-00536-en)
which uses ratios of PPPs for private final consumption expenditure to exchange rates. The monthly PPPs used to derive the table are OECD estimates. I don't think they would give it out to the public as this may be an internal series they use (which may have quality issues) but its worth contacting them about it.