For each wallet you can create unlimited number of addresses, in case if each of addresses will be used. Otherwise you can create no more than three addresses per day.
To create a new address select the "Accounts" section, then chose the wallet where you want to create the address and select "Addresses". Pick the currency for this address and click the "New" button.
Choosing a currency which differs from the currency on your wallet you will deal to automatic conversion which is carried out at the market price, according to service fees.