can i deposit in any currency into my trading account?

Yes, you can deposit in any currency and the broker will convert it into your account currency and there is a fee for the conversion which you don't always see, because it is built into the exchange rate.

Yes, you can deposit in your local currency and but there is a currency conversion fee for turning it into your account display currency. To avoid this fee, it is better to set your account currency (aka base currency) to be the same with the currency you hope to be depositing in most of the time.

For example I am in South Africa so to avoid being charged a conversion fee on deposits & withdrawals I opened by trading account in South African Rand since that's the local currency here.