You can select to insert full posts or excerpts in the visual editor.
This is option is available in 2 places. When you insert posts:
Or when you insert latest posts for auto newsletters (starting in version 2.0):
Which excerpt does Wysija prioritize?
1. manual excerpt, which is an extra field in your post’s page:
2. The more tag, which is you the user select when writing a post:
3. The first 60 words, if none of the two above are set.