A great benefit of futures is that they allow a trader to participate in a market for a fraction of the contract’s face value.
To do this the exchange will require every participant to place a margin with them for each contract/position they’re in.
Margins ensure the integrity of futures trading where all trades are honoured.
Margins change regularly due to market volatility so you should always consult with your broker about what is required.
I use Interactive Brokers.
The following is a link to their margin page.
The table below gives you an indication of margin requirements from contracts within my currency, index and universal diversified portfolios.