While these two haven't had many interactions in the show, the times they have been together have made this ship semi-popular. The two have very contrasting personalities. Todoroki is more introverted while Uraraka is more social. One thing they have in common is that they express their true feelings quite minimally, Uraraka smiling through nearly everything while Todoroki usually frowns.
Both had comparatively difficult childhoods. Uraraka has grown up in a poor household with a strong and healthy bond with her parents, while Todoroki has always been rich, but has grown up in an abusive household.
They seem to have rather different fathers. Ochako's father has always been supportive, loving, caring, and selfless towards Ochako's dreams, and wishing for her happiness. Shoto's father has been very violent and selfish, not caring about the wishes of his wife or son.
Forest Training Camp
Todoroki used his fire to help Uraraka, and it took him until Uraraka told him something for him to smile (which is something he rarely does).
When Todoroki told Uraraka to handle an unconscious person, he most likely took into account that her Quirk would make it easy.
My Hero Academia: Two Heroes
Todoroki had taken the time to guard Uraraka.
TodoChako is rather a rarepair in the fandom. Most of the MHA fans are either pretty neutral about this pairing or unaware of its existence.