Is there a way to add content templates for blog I've been asked to add templates (where a blog post is pre-created with certain content) and the user simply selects it and make minor changes. Please note this is not a visual template, but a content one.

Thanks!
Go to Manage fields

Ex: /admin/structure/types/manage/article/fields

Then click on edit, for example, the body field. Look for Default Value and put whatever you want there.

Now when a user tries to add a new article, it will have the body pre-filled-out and they can change it if they wish.