Blog settings are located in Appearance > Customize > Content Options > Blog.
These settings will be applied to all blog posts. Here you can choose to display the full post or excerpt, choose the posts layout, change the number of posts columns, specify the maximum length of the excerpt or remove it, add/remove button and so on.
If you would like to configure the archive (category and search results layout), go to Appearance > Customize > Content Options > Archive & Search Results.