There is an OTC company that has very low trading volume. Today from the “trade page” it shows that 20,000 Shares were sold but in the buyers column it shows zero amount of shares bought, the stock is pretty stagnant, many days zero trading . It is selling around 31 cents been around for about 9 years with a Lot of history. Who is buying the stock?
One of the characteristics of the OTC market is that the trades aren't 'public' in the same way that trades on exchanges are.
A trade can be executed between two participants in an OTC market without others being aware of the price at which the transaction was completed. - investopedia
So in relation to your question about "Who is buying the stock?" - the OTC broker might never disclose to the public who bought the stock.
As you are seeing, not all trades take place in the light of day. Even 'regular' stocks like AAPL and AMZN are not always publicly traded in the sense that anyone can see anyone else's trade activity (even anonymously).
There exist all sorts of dark pool and closed markets where trades may take place without their contents being publicly reported. That is not to say that these transactions take place outside of the established systems - FINRA and other federal and market agencies still oversee all trades and will be involved in stages of the execution and settlement processes, but you can think of it as being 'behind closed doors'.