Inside your numberlab dashboard, you can now add tags to numbers to help categorize and search for them. To start login to your dashboard and navigate to the numbers tab on the top of the screen
From here you can add tags to individual numbers by selecting the edit button on the right side of the screen for the number you want to apply a tag to. From here you will be able to create a new tag or select existing tags to be applied to this phone number. Note that you can add as many tags as you want to each phone number. Additionally, this is where you will come to delete tags from a number.
Once you have applied the desired tags and returned to the numbers tab by selecting "numbers" at the top of the screen, You can now search by tags to filter your numbers. Note if you are having trouble selecting a tag be sure to click the green + button when you hover over the tag.