Sindhu, if you post a screen shot of the sheet you are trying to put the logo on, I can give you some options.
Within the dashboard there is an ability to add an image that can link to a handful of image types. Within a workbook, one option to look at is using a shape where the shape is your image - not difficult to setup, but it has limitations and may not work well in all instances. Per Shawn's earlier post, more info on what you are trying to accomplish and where would be helpful.
The following KB article online help article explains how to do this in Tableau Server:
And the following KB article describes how to add it to a dashboard as Andy described using an image:
Hope one of these provides some insight!
I understand what you are trying to do as I am in need to figure this out as well.
Sindhu wants to add a logo to a sheet not a Dashboard. Correct? Is this possible?
Dashboards print to one sheet only but sheets can print out to multiple sheets. The problem is that I want to remain consistent and insert a logo.
If anyone has a solution, it would be greatly appreciated!