What is the ruling on working on the Freelancer website, and is it permissible to subscribe to it monthly or annually to gain greater privileges and benefits?

There is no objection to a person showcasing their work and skills and bidding on them. There is also no impediment to subscribing to a premium membership that allows for an increased number of entries into bids. This payment is in exchange for enabling the worker to present their work, whether the fees are imposed from the first time or after a certain number of free attempts.