There are a lot of rules regarding how you should write out the hosts' names, depending on who the hosts are. Generally, the hosts related to the bride go first, followed by the groom's relatives.
If the parents of the bride or groom are still married write “Mr. and Mrs." followed by the bride's father's name. So Tiffany Smith's parents should be written as "Mr. and Mrs. John Smith” or “Mr. and Mrs. James Carter” on the first line of the invitation. The groom's parents should be written the same way, on the third line (with "and" on its own on the second line). If both families – including the bride and groom – are hosting, you should write “Together with their families," on the first line, then the name of the bride, "and," and the name of the groom on the second, third, and fourth lines respectively. If the bride’s parents are divorced and remarried but hosting together, you should write list the mother's new name first, followed by the father's name. So for example, you might write “Mr. and Mrs. Jill Willby and Mr. and Mrs. Greg Smith." Again, each couple gets their own line with “and” on the second line. If someone other than parents or stepparents are hosting, write the host(s) name(s) and their relationship to the bride or groom. So, for example, if the bride’s brother is hosting, you should write “Mr. Stanley Smith requests the honor of your presence of the marriage of his sister Stephanie Smith.”