Google Spreadsheet- What to do if the MSG91 Add-On option is not available in the Plugin after installation?

Video :
 

If after installation of Google Sheet Add-On, the plugin will not visible after opening the sheet again then follow the below steps. 

1. Click on Extension, hover to Add-ons, and then click on Manage add-ons.

2. Click on the three dots.

 

3. Select use in this document option.

4. Click on Extension, hover to Add-ons, and then click on use in this document.

After this Add-On will be available in your extensions for new and old Google sheets.