Hello @Richelle Lanuza ,
Thank you for reaching out to the Microsoft Q&A platform. Happy to answer your question.
If this is a CSV, then please follow the procedure from this link extending-CSV
another reference : https://social.technet.microsoft.com/Forums/en-US/7cbab72f-ec60-4355-ac0a-42769cd6476f/windows-2016-storage-pool-expand-physical-disks
https://video2.skills-academy.com/en-us/answers/questions/166041/cluster-shared-volume-volume-size-increase.html
If this is a storage space direct (S2D) which is a new type of storage Microsoft added in windows server 2016. Then you can follow the procedure from the following link how-to-expand-and-resize-storage-spaces-direct-csv-volume-ws2016-hyperv-s2d
Hope this helps, if not, please respond to this answer in a commen and I will be more than happy to guide further.
Please "Accept as Answer" and Upvote if the answer provided is useful, so that you can help others in the community looking for remediation for similar issues.