There are 3 ways to add targets in a workspace
1. Automatically from the tool page
A target is automatically added to your current workspace when you run a scan against it from the tool page. It will be suggested in the target field what sort of target you need to add for that particular scanner: IP, hostname or URL.
2. From the /targets page
You can add a single target by clicking on the +Add button
You can add multiple targets at once by importing a .txt file. Make sure that the text file you are uploading contains one target per line.
3. From the results of a discovery scan
Targets can also be added from scan results. For example, Find Subdomains. You can select the results by clicking the checkbox next to them and click the Add to Targets button so they will be automatically added to your Targets.