Hi Ayushi,
It simple and easy, follow the below steps:
1. Create the main visualization and secondary visualization.
2. Now click on tooltip in the primary or main visualization.
3. In the dialog box, click the insert dropdown and go to sheets.
4. Select the sheet that you want to appear in the tooltip.
5. Click ok.
For ex:
For more information visit here,
https://www.tableau.com/learn/tutorials/on-demand/viz-tooltip?product=tableau_desktop%2Btableau_prep&version=tableau_desktop_2019_1%2Btableau_prep_2019_1_2&topic=visual_analytics
Hope it helps.