You will find the flag in the outcome qualification section. You can also add information about HTQs in the Course Summary section of your courses in the collection tool. Using the flag will ensure these courses are listed when the HTQ filter is applied in Search and they will have the HTQ branding included on the course details page in search.
If you have any questions about this the Data Collection Team will be happy to help at coursesdata@ucas.ac.uk or 01242 544864.