To create Address instance you can use constructor with different overloads:
string addrStr = ""; // base 64 or raw address string representation
int workchain = 0; // address workchain
byte[] hash = /* 32 bytes of the address hash value */;
StateInit stateInit = /* address state init */;
// Initializes a new instance of the Address class based on a string representation of the address
Address addr1 = new Address(addrStr);
// Initializes a new instance of the Address class based on an existing address.
Address addr2 = new Address(addr1);
// Initializes a new instance of the Address class based on address workchain and hash.
Address addr3 = new Address(workchain, hash);
// Initializes a new instance of the Address class based on address workchain and state init.
Address addr4 = new Address(workchain, stateInit);
You can use ToString() method with different parameters to convert Address instance into string representation: