Document Viewer enables you to view documents directly in the Now Platform rather than having to download them.
Supported File Types
MS Word (.doc) and (.docx)
MS PowerPoint (.ppt) and (pptx)
MS Excel (.xls) and (.xlsx)
Image Files (png, .jpg)
Other document types, for example, zip, exe are automatically downloaded.
Document viewer does not support
File sizes over 50MB
More information from the ServiceNow Documentation
STep 1: Activate Document Viewer
Login as admin
Left Navigator Bar → System Definition → Plugin
Enter Document Viewer (com.snc.documentviewer) in the Search field.
Step 2: Activate Document Viewer (Table Level)
Activate Document viewer for selected tables
Navigate to System Definition → Dictionary.
Open the table you want to use the document viewer and click New under the Attributes tab.
Enter Use Document Viewer in the Attribute field.
Enter true in the Value field.