When handwriting, the following formatting is typically used:
- The name of a character on a television show: Regular text (no underline)
- The name of the channel television show is on: Regular text (no underline)
- The title of a television show: Underline
- The title of an episode of a television show: Use quotation marks (e.g., "Episode Title")
So, when handwritten, you should underline the title of a television show.