ReadWorks.org and Newsela are excellent free resources for teacher to find quality short reading passages by grade or reading level, genre and/or reading skill/strategy. Look for a passage that has questions, particularly an open-ended response, associated with the reading.Scholastic News and Time for Kids would also be a useful resource for passages and questions.
Once you have a reading passage and question(s) selected, you will open your Google Drive and make a Google Form that your students can access to write their response after they have read the passage. Above is an example of how a Reading Passage Short Answer Response Form might look.
Once the students have submitted their form, you will have access to the students' responses in a Google Sheet. This document will be created by Google as an option when you publish the Form.