You mean, if I buy 0.000747828 + withdrawal fee, I would be able to withdraw the whole thing?
Basically, yes, you can transfer any amount you want from one wallet to another. But, keep in mind that transaction fees on the Bitcoin network are quite high at the moment. The question of cost effectiveness...
How can I deposit the "missing" BTC amount?
That depends on the specific platform. Check their terms or customer support.