Excerpts and Full Content Display
On your blog page you can choose between setting an excerpt (a shortened version of the post) or the full content of the post.
Thrive Theme Setting
In order to change this setting you should go to "Thrive Dashboard":
In the Thrive Dashboard, click on the Theme options button of your themes card:
In the theme options, you can then go into the section that says "Blog Settings":
If you choose "Post Excerpt", WordPress will automatically generate an excerpt (When a post has no manual excerpt, WordPress generates an excerpt automatically by selecting the first 55 words of the post).
If you choose "content", WordPress will look for the More tag and create a teaser from the content that precedes the More tag.
How to add manual excerpts (WordPress official documentation)
Using the WordPress More Tag (WordPress official documentation)
Using the "More" tag with Thrive Architect (Thrive Themes knowledge base article)