You can easily collect approval from your end-users through the checklist by playing with the different features based on your needs.
Getting approval on files you share first
You want (A) to share files with your end-users and (B) get their approvals on these files. We'll suggest this combination, don't worry it's pretty straightforward.
File sharing + Task line item + Instructions + Messaging system
A/ If you're adding this requirement at a process level, go to Configuration> File sharing to add your files. If you're in a live application, go to More options>File sharing to add your files
B/ Go back to your checklist, then click on the "Add new steps" blue button to add a task line item.
Add your instructions in the related field and Click on "Get attachment link" to grab the shared file link.
Don't hesitate to invite end-users to share approval through the messaging system.