i am not able to type in add your user under service setup

@Harshita Shah,

I believe you have consumed both of your licenses. Right below your profile field can you see something like (2/2) ? If so then yes you do not have a user license to add a new user.

As the module mentioned, If you've used the maximum number of licenses allowed in your current playground, please deactivate one of the licenses and then add Ada. Alternatively, you can create a new playground.

https://trailhead.salesforce.com/help?article=Data-Security-Trailhead-Challenge-Help&topic=Hands_on_Challenge&topicName=Hands-on%20Challenge&groupName=Trailhead_Support

Check this similar issue thread: 

• https://trailhead.salesforce.com/trailblazer-community/feed/0D54S00000A91HBSAZ
• https://trailhead.salesforce.com/trailblazer-community/feed/0D54S00000El55dSAB