1- Comment and review PDFs: With Reader on your desktop, you can: annotate PDFs using sticky notes; type text directly onto the page; highlight, underline, or use strikethrough tools; and draw on the screen with the freehand drawing tool. Guide: https://helpx.adobe.com/in/acrobat/using/commenting-pdfs.html
2- Fill & Sign PDF Forms: An interactive or fillable form contains fields that you can select or fill in. For such forms, the Fill & Sign tool displays only the Sign option. For more information on filling an interactive form, see Fill in interactive forms.
3- Share PDF: You can quickly share a link to a PDF document with others for viewing or commenting. The document shared as a link opens in any browser, on any device. The document is stored securely in Adobe Document Cloud.
Use Adobe Document Cloud to store, find, and view files in the cloud. When you save files in the cloud, you can access them from virtually any device. Document Cloud services are also integrated with Acrobat DC, Acrobat Reader DC.
Sign in to Adobe Document Cloudwith your Adobe ID and password, or with your social (Facebook, Google, or Apple) account.
5- Certificate-based signatures: A certificate-based signature, like a conventional handwritten signature, identifies the person signing a document. Unlike a handwritten signature, a certificate-based signature is difficult to forge because it contains encrypted information that is unique to the signer. It can be easily verified and informs recipients whether the document was modified after the signer initially signed the document.
To sign a document with a certificate-based signature, you must obtain a digital ID or create a self-signed digital ID in Acrobat or Adobe Reader.