please explain to me these questions.

1) what is the initial margin?

As far as I've known, this is the required amount of money we should deposit in order to do trading and such. But I'm wondering if we can't withdraw the initial margin once deposited?

2) Should we pay the initial margin every time we trade and such?

PNL Target Price Liquidation Price Max Open Open Price Long Short Result 3x Initial Margin 302.12 USDT 1x 10x 20x 30x 40% 50x PNL 23.24 USDT Maximum position at current leverage: 250,000 USDT ROE 7.69 % Entry Price 0.78 USDT Exit Price 0.80 USDT Quantity 1162 SAND Calculate