"To facilitate the transaction" means to make it easier or smoother for a transaction (like buying or selling something) to happen between two parties. Full definition
The lawyer told his client he would help facilitate the transaction in exchange for a percentage of the client's inheritance. (lawyerist.com)
Until now, the cryptocurrency space has been dominated by centralized exchanges that help facilitate transaction from government currencies to cryptocurrencies. (coindesk.com)
For businesses that develop the payment systems, there are of course profits if the systems are widely adopted — and often the systems facilitate transactions with other businesses of the developer itself. (slaw.ca)