# Commenting, meetings, and digital signatures

If the PDF initiator has granted additional usage rights, you can use the commenting and markup tools to review PDFs and manage, import, and export your review comments. Use Acrobat Connect to start online meetings, and work with digital signatures to verify identities when working with others electronically.

- Quickstart
- Reviewing and commenting
- Meetings
- Digital signatures
- Signing PDFs
- Validating signatures