In 'The Life and Adventures of Santa Claus' by L. Frank Baum, author of the famous 'The wonderful Wizard of Oz, he does not have a wife'. It tells the youth, manhood and old age of Santa. But there are as well other sources: "A Christmas Legend "(1849) by James Rees, there he got a wife.

In the United States, the situation is ambiguous. The core of the Santa Claus story is described in a famous poem. Many people in the US know big parts of it by heart. It's usually called by its first line, "'Twas the Night Before Christmas," although the title is really "A Visit from St. Nicholas.") It was published anonymously in 1823. Clement Clarke Moore later said he was the author, and it's usually attributed to him. You can read it here. https://www.poetryfoundation.org/poems/43171/a-visit-from-st-nicholas The poem describes "St. Nick" flying on a sleigh, drawn by eight reindeer, landing on rooftops, climbing down the chimney, and delivering toys. The poem says nothing about where Santa Claus lives. Other parts of the tradition say that he lives at the North Pole where he and his elves make the gifts in a workshop. This part of the tradition may have been crystallized and popularized by a series of 1880 cartoons by Thomas Nast. If someone telling a story about Santa mentions more than the workshop, then, yes, they will usually say that he has a wife named "Mrs. Claus." They do not have children.

Thank you for letting me know everyone :) Wow, Mrs Claus ⁉️ Is it well known story? That’s interesting. I didn’t know never ever. I‘ve thought that he lived alone with reindeers. 🎄🎄🎄🎄 Finally, Happy Christmas to you! (a little bit earlier though...)

Traditionally he only has his wife, Mrs. Clause

Yes, he does. Although Mrs. Claus' 1st name is somewhat of a mystery.