The Search and Explore lets you search OKRs with their associated Tags and export them in excel.
To find Search by Tag go to Search and Explore OKRs:
Click the arrow button of Search and Explore, which is placed to left side of selected period.
You can click Search by Tag button as shown in the pic below:
Witsmate 'Search by Tag' feature allows you to see how those Objectives and associated Key-Results are progressing. You can enter a maximum of 5 Tags as identifiers.