Anil Shewale
Mega Guru

hi Steven Karl

refer the following thread you can make field mandatory using onsubmit client script and script include refer the following thread it similar to your question.

https://community.servicenow.com/community?id=community_question&sys_id=60ebf7a4dbbdf3c82be0a851ca96...

https://community.servicenow.com/community?id=community_question&sys_id=832bc7eddb5cdbc01dcaf3231f96...

 

If it help mark helpful or correct.

Thanks and regards

Anil