1. Here are some things you can do from the Google Drive viewer:
Show revision history of the file (if you have owner or edit rights)
Change the sharing settings (if you have owner or edit rights)
Download and print by going to the File menu and selecting Download as...
Search text on the page using the search box in the upper right.
Add your comments in all types of files.
Only files under 25 MB can be previewed with the Google Drive viewer.
Google Drive viewer helps you preview over 16 different file types, listed below:
Image files (.JPEG, .PNG, .GIF, .TIFF, .BMP)
Video files (WebM, .MPEG4, .3GPP, .MOV, .AVI, .MPEGPS, .WMV, .FLV)
Text files (.TXT)
Markup/Code (.CSS, .HTML, .PHP, .C, .CPP, .H, .HPP, .JS)
Microsoft Word (.DOC and .DOCX)
Microsoft Excel (.XLS and .XLSX)
Microsoft PowerPoint (.PPT and .PPTX)
Adobe Portable Document Format (.PDF)
Apple Pages (.PAGES)
Adobe Illustrator (.AI)
Adobe Photoshop (.PSD)
Tagged Image File Format (.TIFF)
Autodesk AutoCad (.DXF)
Scalable Vector Graphics (.SVG)
PostScript (.EPS, .PS)
TrueType (.TTF)
XML Paper Specification (.XPS)
Archive file types (.ZIP and .RAR)

2. Google Drive is also connected directly to Gmail. If you receive an attachment in Gmail, you can
click the ‘View’ link, which will display that file attachment through the Google Drive viewer.
Action Shortcut
Open Ctrl + O
Download Ctrl + S
Play/Pause Video Space
Compact controls Ctrl + Shift + F
Editdescription Ctrl + Alt + E
Open Ctrl + O